Improving sustainable hydrogen production from green waste: [FeFe]-hydrogenases quantitative gene expression RT-qPCR analysis in presence of autochthonous consortia

BACKGROUND

Bio-hydrogen production via dark fermentation of low-value waste is a potent and simple mean of recovering energy, maximising the harvesting of reducing equivalents to produce the cleanest fuel amongst renewables. Following several position papers from companies and public bodies, the hydrogen economy is regaining interest, especially in combination with circular economy and the environmental benefits of short local supply chains, aiming at zero net emission of greenhouse gases (GHG). The biomasses attracting the largest interest are agricultural and urban green wastes (pruning of trees, collected leaves, grass clippings from public parks and boulevards), which are usually employed in compost production, with some concerns over the GHG emission during the process. Here, an alternative application of green wastes, low-value compost and intermediate products (partially composted but unsuitable for completing the process) is studied, pointing at the autochthonous microbial consortium as an already selected source of implementation for biomass degradation and hydrogen production. The biocatalysts investigated as mainly relevant for hydrogen production were the [FeFe]-hydrogenases expressed in Clostridia, given their very high turnover rates.

RESULTS

Bio-hydrogen accumulation was related to the modulation of gene expression of multiple [FeFe]-hydrogenases from two strains (Clostridium beijerinckii AM2 and Clostridium tyrobutyricum AM6) isolated from the same waste. Reverse Transcriptase quantitative PCR (RT-qPCR) was applied over a period of 288 h and the RT-qPCR results showed that C. beijerinckii AM2 prevailed over C. tyrobutyricum AM6 and a high expression modulation of the 6 different [FeFe]-hydrogenase genes of C. beijerinckii in the first 23 h was observed, sustaining cumulative hydrogen production of 0.6 to 1.2 ml H₂/g VS (volatile solids). These results are promising in terms of hydrogen yields, given that no pre-treatment was applied, and suggested a complex cellular regulation, linking the performance of dark fermentation with key functional genes involved in bio-H₂ production in presence of the autochthonous consortium, with different roles, time, and mode of expression of the involved hydrogenases.

CONCLUSIONS

An applicative outcome of the hydrogenases genes quantitative expression analysis can be foreseen in optimising (on the basis of the acquired functional data) hydrogen production from a nutrient-poor green waste and/or low added value compost, in a perspective of circular bioeconomy.

Ligand stabilization and effect on unfolding by polymorphism in human flavin-containing monooxygenase 3

Pharmacogenomics is a powerful tool to prevent adverse reactions caused by different response of individuals to drug administration. Single nucleotide polymorphisms (SNPs) represent up to 90% of genetic variations among individuals. Drug metabolizing enzymes are highly polymorphic therefore the kinetic parameters of their catalytic reactions can be significantly influenced. This work reports on the unfolding process of a phase I drug metabolizing enzyme, human flavin-containing monooxygenase 3 (hFMO3) and its single nucleotide polymorphic variants (SNPs) V257M, E158K and E308G. Differential scanning calorimetry (DSC) indicates that the thermal denaturation of the enzyme is irreversible. The melting temperature (T_m) for the (Wild Type) WT and its polymorphic variants is found to be in a range from 46 °C to 50 °C. Also the activation energies of unfolding (E_a) show no significant differences among all proteins investigated (290-328 KJ/mol), except for the E308G variant that showed a significantly higher E_a of 412 KJ/mol. The presence of the bound NADP⁺ cofactor is found to stabilize all the variants by shifting the main T_m by 4-5 °C for all the proteins, exception made for E308G where no changes are observed. Isothermal titration calorimetry (ITC) was used to characterize the interaction of the protein with NADP⁺ in terms of dissociation constant (K_d), enthalpy (ΔH) and entropy (ΔS). K_d values of 1.6 and 0.7 μM, ΔH of -13.9 Kcal/mol and -16.8 Kcal/mol, ΔS of -20.5 cal/mol/deg, and -28.5 cal/mol/deg were found for V257M and E158K respectively. E308G was found to be unable to bind the NADP⁺ cofactor, a result that is in line with the T_m results. Circular dichroism also confirmed an overall lower stability of E308G, while NADP⁺ was found to give a strong positive shift of the T_m stabilizing the structure of E158K (46.2 to 50.6 °C). Previous data highlighted significant differences in terms of activity among the SNPs of hFMO3. In this work a minor impact of the SNPs was found on the stability of the enzyme in the ligand free form, except for E308G, whereas the binding of NADP⁺ reveals major differences among WT and polymorphic variants that are all measurable in terms of heat capacity, enthalpy and secondary structure content. These data provide the first direct evidence of ligand stabilization effects on hFMO3 that can explain the differences observed in catalytic efficiencies and serve as the starting point for the development of inhibitors of this enzyme.

Influence of different biological control agents and compost on total and nitrification-driven microbial communities at rhizosphere and soil level in a lettuce - Fusarium oxysporum f. sp. lactucae pathosystem

AIMS

The response of rhizosphere and bulk soil indigenous microbial communities focusing on nitrifiers was evaluated after the application of different biological control agents (BCAs; Bacillus, Trichoderma, Pseudomonas) and compost in controlling lettuce Fusarium wilt.

METHODS AND RESULTS

Experiments were conducted 'in situ' over two lettuce cropping seasons. Total fungal, bacterial and archaeal populations and the nitrifiers were analysed using quantitative polymerase chain reaction method. The pathogen, Fusarium oxysporum forma specialis lactucae (FOL), Bacillus, Trichoderma and Pseudomonas and three antifungal genes (chiA, 2,4-diacetylphloroglucinol - phlD and HCN synthase - hcnAB genes) were also assessed. Quantitative data were corroborated with disease severity (DS), potential nitrification activity and soil chemical parameters. The application of BCAs and compost resulted in the disease reduction by as much as 69%, confirmed by significant negative correlations between Bacillus subtilis, Trichoderma and Pseudomonas sp. abundances and DS. The FOL presence in the untreated control resulted in the nitrifiers niche differentiation.

CONCLUSIONS

The used treatments were efficient against Fusarium wilt and did not influence negatively the nontarget microbial communities.

SIGNIFICANCE AND IMPACT OF THE STUDY

The use of BCAs and compost appears as an effective and safe strategy to implement sustainable agricultural practices.

Verrucarin A and roridin E produced on rocket by Myrothecium roridum under different temperatures and CO2 levels

The behaviour of Myrothecium roridum, artificially inoculated on cultivated rocket (Eruca sativa), has been evaluated under eight different temperature and CO2 concentration combinations (from 14-18 °C to 26-30 °C and with 400-450 or 800-850 ppm of CO2). The pathogen isolate used for this study was inoculated on rocket and disease severity increased with high temperatures for both CO2 levels. Verrucarin A and roridin E mycotoxins were produced under all the tested temperatures at high CO2 conditions. The maximum level of verrucarin A was found at 14-18 °C and 800-850 ppm of CO2, and the maximum roridin E production was detected at 26-30 °C with 800-850 ppm of CO2. The results obtained in this study show that both the CO2 concentration and the temperature influence disease severity and mycotoxin production in different ways. An increase in temperature, which is favourable for attacks of the pathogen, could induce the spread of M. roridum in temperate regions, and this pathogen could take on even greater importance in the future, considering its ability to produce mycotoxins.

Extended C-band tunable multi-channel InP-based coherent receiver PICs

Fully integrated monolithic, multi-channel InP-based coherent receiver PICs and transceiver modules with extended C-band tunability are described. These PICs operate at 33 and 44 Gbaud per channel under dual polarization (DP) 16-QAM modulation. Fourteen-channel monolithic InP receiver PICs show integration and data rate scaling capability to operate at 44 Gbaud under DP 16-QAM modulation for combined 4.9 Tb/s total capacity. Six channel simultaneous operation of a commercial transceiver module at 33 Gbaud is demonstrated for a variety of modulation formats including DP 16-QAM for >1.2Tbit/s aggregate data capacity.

Root Rot of Spinach in Southern Italy Caused by Pythium aphanidermatum

During the spring of 2014, spinach (Spinacia oleracea L.) plants of the cv. Crocodile (Rijk Zwaan, De Lier, The Netherlands), grown in a clay loam soil under commercial greenhouse conditions near Salerno (southern Italy), showed stunting, extensive chlorosis, and root rot. Plants were irrigated by overhead sprinklers using well water. Symptoms first developed 20 days after sowing, at air temperatures of 23 to 30°C, and 35% of plants (approximately 15 million plants in 10 ha) were affected. Roots were severely affected, appeared water-soaked and brown, and were characterized by a soft rot. Eventually, affected plants wilted and collapsed. Fifty fragments, each 1 mm², were excised from symptomatic roots of 10 plants, dipped in a solution containing 1% sodium hypochlorite, rinsed in sterilized water, dried on sterilized paper towel, and plated on both potato dextrose agar (PDA) and the medium BNPRA, which is semi-selective for oomycetes (3). After 5 days of incubation under constant fluorescent light at 22 ± 1°C, 80% of the root sections developed oomycete colonies. One representative isolate, grown for 12 days on V8 agar medium (200 ml V8 Campbell Soup; 15 g agar; 0.5 g CaCO₃; 1 liter distilled water) and observed with a light microscope, showed aseptate hyphae 3.3 to 6.5 (mean 5.5) μm wide. Oogonia were globose, smooth, and 22.2 to 31.0 (average 26.3) μm in diameter. Antheridia were barrel-shaped, while oospores were globose and 17.3 to 22.6 (mean 20.9) μm in diameter. These morphological characters identified the microorganism as a Pythium sp. (4). The internal transcribed spacer (ITS) region of ribosomal DNA (rDNA) of this isolate was amplified using ITS1/ITS4 primers and sequenced. BLAST analysis (1) of the 647-bp segment showed 100% homology with ITS sequences of Pythium aphanidermatum in GenBank (Accession Nos. KJ755088.1, KJ162355.1, KF840479, and KF561235.1). The nucleotide sequence for the Italian spinach isolate was assigned No. KM111256. Pathogenicity tests were performed twice on 20-day-old spinach plants of the cv. Merlo (L'Ortolano, Cesena, Italy), grown in 2-liter pots in a steam-disinfested organic peat substrate (black peat, pH 6.5 to 6.8, N 110 to 190 mg/liter, P₂O₅ 140 to 230 mg/liter, K₂O 170 to 280 mg/liter) moistened to field capacity, and infested with wheat and hemp kernels colonized with isolate Py 1-14 of P. aphanidermatum at 1 g/liter. Five plants were transplanted into each of four pots filled with infested peat, while the same number of plants was grown in non-infested substrate as a control. Plants were kept in two growth chambers, each with 12 h of light per day at 20 or 30°C, and were irrigated daily to maintain the potting medium at field capacity. Symptoms first developed 5 days after the spinach was transplanted into infested potting medium in the growth chamber maintained at 30°C. After 10 days, all plants in this growth chamber were dead, while only 5% of the plants growing in infested potting medium in the 20°C growth chamber were affected. Control plants remained asymptomatic at both temperatures. P. aphanidermatum was re-isolated consistently from the symptomatic roots of plants grown in infested medium. No fungi were re-isolated from the asymptomatic control plants grown in non-infested substrate. To our knowledge, this is the first report of P. aphanidermatum causing root rot on S. oleracea in Italy. The same pathogen has been reported to cause root rot of spinach in other countries, including the United States (2). The disease is, at present, limited to the affected greenhouses observed in this study. References: (1) S. F. Altschul et al. Nucleic Acids Res. 25:3389, 1997. (2) M. L. Bates and M. E. Stanghellini. Plant Dis. 68:989, 1984. (3) H. Masago et al. Phytopathology 67:425, 1977. (4) T. Watanabe. Pictorial Atlas of Soil and Seed Fungi. CRC Press, FL., 2002.

PRE-PLANTING TREATMENTS WITH PHOSPHITE-BASED PRODUCTS AGAINST DIFFERENT FOLIAR AND SOIL-BORNE PATHOGENS OF VEGETABLE CROPS

Fifteen experimental trials were carried out under greenhouse conditions to evaluate the efficacy of preventative treatments based on phosphite salts on the following pathosystems: tomato/Phytophthora nicotianae, zucchini/P. capsici, lettuce/Fusarium oxysporum f.sp. Iactucae, rocket/Fusarium oxysporum f. sp. raphani, wild rocket/Plectosphaerella cucumerina and basii/Peronospora belbahrii. The possible use of phosphite salts in nursery cultivation systems is considered in comparison with chemical fungicides. Phosphites-based products reduced 66-88% and 56-72% the severity of Phytophthora crown root rot of tomato and zucchini, respectively. Four application with the phosphites-based products provided a disease reduction of Fusarium wilt of lettuce from of 33 to 83% and of 45 to 68% on cultivated rocket. These products provide the most constant results when applied in three treatments against Plectosphaerella cucumerina with a disease reduction ranging between 34%-82%. Phosphite-based products showed results statistically similar to mefenoxam when tested against downy mildew of basil. Their contribution to disease management can be very interesting, because they can complement other control measures.

EFFECT OF BIOSOLARISATION ON THE MICROBIAL POPULATIONS OF SUBSTRATES INFESTED WITH FUSARIUM OXYSPORUM BY PCR-DGGE

Biosolarisation consists of combining solarisation and organic matter application for controlling soilborne pathogens. The effects of this control strategy on the microbial community is almost unknown and needs to be investigated with molecular tools. The aim of the research was to investigate how biosolarisation can affect the structure of the microbial populations evaluated by a culture independent method using DGGE of PCR-amplified 18S-ITS genes-coding fragments from DNA extracted directly from infested substrate. Substrate samples were artificially infested with Fusarium oxysporum f. sp. conglutinans (FOC) and F. oxysporum f.sp. basilici (FOB) in order to evaluate the shift in fungal population by using culture independent methods. Solarisation was carried out with transparent polyethylene film during the summer period in a greenhouse located in Northern Italy, in combination or not with Brassica carinata defatted seed meals and/or compost. Biosolarisation treatment was carried out in a growth chamber by heating the substrate for 7 and 14 days at optimal (55-52 degrees C for 6 h, 50-48 degrees C for 8 h and 47-45 degrees C for 10 h/day) and sub-optimal (50-48 degrees C for 20 h, 45-43 degrees C for 8 h and 40-38 degrees C for 10 h/day) temperatures. Plate counts and polymerase chain reaction denaturing gradient gel electrophoresis (PCR-DGGE) analyses were performed to evaluate the effect of biosolarisation on the microbial population. The abundance of FOC and FOB was reduced as a consequence of biosolarisation, while bacterial populations were higher compared to control samples during the experiment. PCR-DGGE fingerprints of the ascomycete community obtained from DNA directly extracted from infested substrate samples showed that the use of organic amendments increased the similarity of the fungal populations.

First Report of Root Rot Caused by Pythium aphanidermatum on Bell Pepper (Capsicum annuum L.) in Italy

During July 2012, symptoms of root rot were observed on bell pepper (Capsicum annuum) grown in 2,000 m² of commercial greenhouses near Cuneo in northern Italy. Symptoms first developed 30 to 40 days after transplanting, when greenhouse temperatures ranged from 25 to 30°C, and 10% of the plants were affected. Affected plants were stunted with leaf chlorosis, reduced growth, and sudden wilting. Roots were severely affected with a brown discoloration, water-soaking, and soft rot. Eventually, affected plants collapsed. Tissue fragments of 1 mm² were excised from symptomatic roots, dipped in a 1% sodium hypochlorite solution, and placed on potato dextrose agar (PDA) and an agar medium selective for oomycetes (3). Plates were incubated under constant fluorescent light at 22 ± 1°C for 5 days. An isolate grown for 12 days on V8 agar medium (200 ml V8 Campbell Soup, 15 g agar, 0.5 g CaCO₃, and 1 liter distilled water) showed aseptate hyphae that were 3.5 to 6.3 μm (avg. 5.2 μm) wide. Oogonia were globose, smooth, and 24.3 to 29.0 (avg. 25.1) μm in diameter. Antheridia were barrel-shaped, while oospores were globose, and 17.3 to 23.5 μm (avg. 21.2 μm) in diameter. These morphological characters identified the microorganism as a Pythium sp. (4). The ITS region of rDNA of a single isolate was amplified using the primers ITS1/ITS4 and sequenced. BLAST analysis (1) of the 781-bp segment (GenBank Accession KF840479) showed 100% homology with the ITS sequence of an isolate of Pythium aphanidermatum in GenBank (AY598622.2). Pathogenicity tests were performed twice on 30-day-old plants of C. annuum cv. Cuneo grown in 2-L pots (4 plants/pot), containing a steam-disinfested, organic peat substrate (70% black peat and 30% white peat, pH 5.5 to 6.0, N 110 to 190 mg/liter, P₂O₅ 140 to 230 mg/liter, K₂O 170 to 280 mg/liter) that was infested with wheat and hemp kernels colonized by the isolate of P. aphanidermatum, at a rate of 1 g colonized kernels/liter potting medium. The inoculum was prepared by autoclaving at 121°C for 30 min a mixture of wheat-hemp kernels (2:1 v/v) in a 1-liter flask, to which the bell pepper isolate of P. aphanidermatum was added in the form of colonized agar medium selective for oomycetes plugs. Before use, the inoculated flask was incubated for 10 days at 22°C in the dark. Four plants/pot were transplanted into each of four pots filled with the infested medium/growth chamber, while the same number of plants were grown in non-infested substrate in pots in each growth chamber. Plants were kept in two growth chambers, one set at 20°C and the other at 28°C. Symptoms first developed 7 days after inoculation. After 30 days, 50% of inoculated plants showed brown roots and died in the growth chamber set at 28°C, while only 10% of the plants were symptomatic at 20°C. Control plants remained asymptomatic at both temperatures. P. aphanidermatum was re-isolated consistently from the symptomatic roots of plants grown in the infested soil by using the same protocol as the original isolations, while no fungal colonies were obtained from asymptomatic roots of the non-inoculated control plants. To our knowledge, this is the first report of the presence of P. aphanidermatum on C. annuum in Italy. The same disease was reported in the United States (2). The importance of the disease, although limited in distribution at present to the greenhouses surveyed in northern Italy, could increase in areas where sweet pepper is grown intensively. References: (1) S. F. Altschul et al. Nucleic Acids Res. 25:3389, 1997. (2) D. O. Chellemi et al. Plant Dis. 84:1271, 2000. (3) H. Masago et al. Phytopathology 67:425, 1977. (4) T. Watanabe. Pictorial Atlas of Soil and Seed Fungi. CRC Press, Boca Raton, FL, 2002.

VARIETAL RESISTANCE TO CONTROL FUSARIUM WILTS OF LEAFY VEGETABLES UNDER GREENHOUSE

Fusarium wilts of leafy vegetables are difficult to manage under intensive cropping systems. The objective of this study was to evaluate, in three experimental trials, the susceptibility of commercial cultivars of lettuce, wild and cultivated rocket and lamb's lettuce to Fusarium wilts in orderto provide information to breeders, as well as to growers. Some of the cultivars of lettuce tested were completely resistant to the three races of Fusarium wilt. It is interesting to observe that most of the resistant cultivars were 'Batavia red'. Only few rocket cultivars commercially available show a partial resistant reaction to F. oxysporum f.sp. raphani, while, varietal resistance is not applicable at the moment to control Fusarium wilt of lamb's lettuce. The integration of cultural practices, use of resistant cultivars, when available, chemicals and biological control agents, permit to prevent and manage these important diseases on leafy vegetables for fresh-cut production.

CONTROL OF SOIL-BORNE DISEASES BY DIFFERENT COMPOSTS IN POTTED VEGETABLE CROPS

The composting process and the type and nature of wastes and raw materials influence the maturity, quality and suppressiveness of composts. Variability in disease suppression also depends on the pathosystem, on soil or substrate type, on chemical-physical conditions, like pH and moisture, and on the microbial component of compost. The aim of the research was to evaluate the suppressiveness of composts, originated from green wastes and/or municipal biowastes, and produced by different composting plants located in Europe. The composts were tested against soil-borne pathogens in greenhouse on potted plants: Fusarium oxysporum f.sp. busilici/basil, Pythium ultimum/cucumber, Rhizoctonia solani/bean. Composts were blended with a peat substrate at different dosages (10, 20 and 50% vol./vol.) 14 days before seeding or transplanting. Pythium ultimum and Rhizoctonia solani were mixed into the substrate at 0.5 g of wheat kernels L(-1) 7 days before seeding, while, in the case of Fusarium oxysporum f.sp. basilici, chlamydospores were applied at 1 x 10(4) CFU/g. Seeds of basil, cucumber and bean were sown into 2 L pots in greenhouse. The number of alive plants was counted and above ground biomass was weighed 30 days after seeding. The number of infected cucumber and basil plants was significantly reduced by increasing dosages of composts, but municipal compost was phytotoxic when applied at high dosages compared to green compost. Moreover, municipal compost increased the disease caused by Rhizoctonia solani on bean. The use of compost in substrates can be a suitable strategy for controlling soil-borne diseases on vegetable crops, but results depend on type of composts, application rates and pathosystems.

First Report of Southern Blight Caused by Sclerotium rolfsii on Common Bean (Phaseolus vulgaris) in Italy

Common bean (Phaseolus vulgaris L.) is grown worldwide for consumption of dry or green beans. During late spring of 2012, yellowing and wilting symptoms were observed in a commercial bean field cv. Lingua di fuoco in Cagliari Province (Sardinia, southern Italy) on 30% of plants 4 to 5 months after sowing. The first symptoms developed in May, when temperatures reached 18 to 30°C. Affected plants showed crown rot, necrosis of the cortex, and foliar chlorosis. As disease progressed, plants collapsed. In the presence of abundant moisture, white mycelium developed on the senescent tissue along with light to dark brown sclerotia (3.0 to 4.8 mm in diameter). Symptomatic tissue was disinfested for 1 min in 1% NaOCl and plated on potato dextrose agar (PDA) amended with 25 mg streptomycin sulfate/liter. The fungus that was isolated consistently from symptomatic plants onto PDA at 23°C grew rapidly in culture with silky-white, sterile mycelium, formed light to dark brown sclerotia (each 1.8 to 3.2 mm in diameter) after 7 days, and readily produced aerial hyphae. These morphological features are typical of Sclerotium rolfsii (2). The internal transcribed spacer (ITS) region of ribosomal DNA (rDNA) was amplified for one isolate using ITS1/ITS4 primers (4), and sequenced (GenBank Accession No. KF002510). BLASTn analysis (1) of the 656-bp segment showed 87% homology with the ITS sequence of an S. rolfsii isolate (JF819727). Pathogenicity of one isolate was confirmed by inoculating healthy P. vulgaris plants cv. Lingua di fuoco grown in 2-liter pots in a steamed potting mix containing 50% Tecno2 (70% white peat and 30% clay) and 50% Tiesse 3 (60% white peat, 20% clay, and 20% perlite) (Turco Silvestro terricci, Bastia d'Albenga, SV, Italy). Inoculum consisting of mycelium and sclerotia of the pathogen produced from 10-day-old cultures on PDA was mixed in the soil at 0.5 g/liter substrate. Four 7-day-old plants per pot, with three replicate pots, were used for inoculation. The same number of control plants grown in the same substrate were inoculated with non-colonized PDA as a negative control treatment. The pathogenicity test was repeated. Plants were kept in a growth chamber at 30°C and 85% RH. Inoculated plants developed symptoms of leaf yellowing within 10 days, followed by crown rot, appearance of white mycelium and sclerotia, and eventual wilting. Control plants remained asymptomatic. Isolations from inoculated plants demonstrated the absence of latent infections by the fungus S. rolfsii, but the fungus was not reisolated from non-inoculated control plants. To our knowledge, this is the first report of S. rolfsii infecting P. vulgaris in Italy. Southern blight has been reported on common bean in sub-tropical and tropical areas of the world (3), where it can cause severe crop losses. References: (1) S. F. Altschul et al. Nucleic Acids Res. 25:3389, 1997. (2) J. E. M. Mordue. CMI Descriptions of Pathogenic Fungi and Bacteria No. 410, 1974. (3) H. F. Schwartz et al. Page 20 in: Compendium of Bean Diseases. American Phytopathological Society Press, St. Paul, MN, 2005. (4) T. J. White et al. PCR Protocols. Page 315 in: A Guide to Methods and Applications. Academic Press, San Diego, CA, 1990.

First Report of a New Leaf Spot Caused by Plectosphaerella cucumerina on Field Grown Endive (Cichorium endivia) in Italy

During summer 2012, symptoms of a new leaf spot disease were observed in several commercial fields in Treviglio (Bergamo, northern Italy) on plants of curly (Cichorium endivia var. crispum) and Bavarian (C. endivia var. latifolium) endive (Asteraceae). This crop is widely grown in the region for fresh market. The first symptoms on leaves of affected plants consisted of small (1 mm) black-brown spots of irregular shape, later coalescing into larger spots, up to 10 to 15 mm diameter. Eventually, spots were surrounded by a yellow halo. Particularly, affected tissues rotted quickly under high moisture. Disease severity was greatest at 75 to 90% RH and air temperature between 23 and 30°C, where affected tissues rotted quickly. This disease resulted in severe production losses. On one farm in particular, three different fields totaling 2 ha, 5 to 13% of the plants were affected. Diseased tissue was excised, immersed in a solution containing 1% sodium hypochlorite for 60 s, rinsed in water, then placed on potato dextrose agar (PDA) medium, containing 25 mg/liter of streptomycin sulphate. After 5 days, a fungus developed producing a whitish-orange mycelium when incubated under 12 h/day of fluorescent light at 23°C. The isolates obtained were purified on PDA. On this medium, they produced hyaline elliptical and ovoid conidia, rarely septate, measuring 5.0 to 9.0 × 1.7 to 3.9 (average 6.0 × 2.9) μm. Conidia were born on phialides, single, clavate, and 2.8 × 1.4 μm. Such characteristics are typical of Plectosphaerella sp. (1,2). The internal transcribed spacer (ITS) region of rDNA was amplified using the primers ITS1/ITS4 (3) and sequenced. BLAST analysis of the 530-bp segment obtained from C. endivia var. crispum isolate PLC28 and of the 527-bp from C. endivia var. latifolium isolate PLC 30, respectively, showed 99% similarity with the sequence of Plectosphaerella cucumerina (anamorph Plectosporium tabacinum), GenBank EU5945566. The nucleotide sequences of isolates PLC 28 and PLC 30 have been assigned the GenBank accession numbers KC293994 and KC293993, respectively. To confirm pathogenicity, tests were conducted on 30-day-old C. endivia plants. C. endivia var. crispum cv Myrna and C. endivia var. latifolium cv. Sardana plants, grown in 2-liter pots (1 plant per pot, 10 plants per treatment) were inoculated by spraying a 10⁶ CFU/ml conidial suspension of the two isolates of P. cucumerina, prepared from 10-day-old cultures, grown on PDA. Inoculated plants were maintained in a growth chamber at 25 ± 1°C and 90% RH for 5 days. Non-inoculated plants, only sprayed with water, served as controls. All plants inoculated with the two isolates, showed typical leaf spots 7 days after the artificial inoculation, similar to those observed in the field. Later, spots enlarged and leaves rotted. Non-inoculated plants remained healthy. P. cucumerina was reisolated from inoculated plants. The pathogenicity tests were conducted twice with identical results. This is, to our knowledge, the first report of P. cucumerina on endive n Italy, as well as worldwide. Due to the importance of the crop in Italy, this disease can cause serious economic losses. References: (1) A. Carlucci et al. Persoonia 28:34, 2012. (2) M. E. Palm et al. Mycologia 87:397, 1995. (3) T. J. White et al. PCR Protocols: A Guide to Methods and Applications. M. A. Innis et al., eds. Academic Press, San Diego, 1990.

First Report of Damping-off Caused by Pythium aphanidermatum on Leaf Beet (Beta vulgaris subsp. vulgaris) in Italy

During July 2010, symptoms of crown and root rot were observed on leaf beet (Beta vulgaris L. subsp. vulgaris) grown in a commercial field near Torino (northern Italy). The first symptoms developed 25 days after sowing with temperatures ranging from 25 to 30°C, and 20% of plants were affected. Affected plants were stunted and leaves showed chlorosis and suddenly wilted. The collar and young stems were affected first and appeared brown, water-soaked, and were characterized by a soft rot. Eventually, all affected plants collapsed. Thin aerial mycelia were visible on the surface of the infected plants if maintained at a high relative humidity. Tissue fragments of 1 mm² were excised from the margins of the lesions, dipped in a solution containing 1% sodium hypochlorite, and plated on potato dextrose agar (PDA) and on a medium selective for oomycetes (2). Plates were incubated under constant fluorescent light at 22 ± 1°C for 5 days. Five isolates, grown on V8 medium (vegetable mix 300 g; agar 15 g; CaCO₃ 1.5 g; distilled water 1 liter) and observed under light microscope showed the morphological characters of Pythium aphanidermatum (3). This result was confirmed by PCR and sequence analysis. The internal transcribed spacer (ITS) region of rDNA of a single isolate (Py 7/10) was amplified using the primers ITS1/ITS4 and sequenced. BLAST analysis (1) of the 815 bp segment showed a 99% homology with the sequence of P. aphanidermatum (GenBank Accession JN695786). The nucleotide sequence has been assigned to the GenBank Accession JX462954. Pathogenicity tests were performed twice on B. vulgaris subsp. vulgaris grown in 2-liter pots, containing a steam disinfested organic peat substrate (70% black peat, 30% white peat, pH 5.5 to 6, N 110 to 190 mg L^-1, P₂O₅ 140 to 230 mg L^-1, K₂O 170 to 280 mg L^-1), infested with wheat and hemp kernels colonized with a strain of P. aphanidermatum at a rate of 1 g L^-1. Ten seeds per pot were sown in four pots filled with the infested medium, while the same number of seeds were sown in non-infested substrate. Plants were kept in two growth chambers, at 20 and 27°C. The first symptoms developed 7 days after the artificial inoculation. After 20 days, 70% of plants were infected at 27°C, while 10% were affected at 20°C. Control plants remained healthy at both temperatures. P. aphanidermatum was consistently reisolated from the lesions. To our knowledge, this is the first report of damping off of B. vulgaris subsp. vulgaris caused by P. aphanidermatum in Italy. The importance of the disease, at present limited, could increase in areas where leaf beet is intensively grown. References: (1) S. F. Altschul et al. Nucleic Acids Res. 25:3389, 1997. (2) H. Masago et al. Phytopathology 67:425, 1977. (3) T. Watanabe. Pictorial Atlas of Soil and Seed Fungi. CRC Press, Florida, 2002.

Effect of silicates and electrical conductivity on Fusarium wilt of hydroponically grown lettuce

Silicon can stimulate natural defense mechanisms in plants, reducing foliar diseases like powdery arid downy mildew on several crops, including lettuce. The effect of silicate on Fusarium wilt, caused by Fusarium oxysporum f. sp. lactucae was evaluated under greenhouse conditions on lettuce grown in soilless systems. Silicon, as potassium silicate, was added at 100 mg L(-1) of nutrient solution at three levels of electrical conductivity; 1.5-1.6 mS cm(-1) (E.C.1), 3.0-3.2 mS cm(-1) (E.C.2) and 4-4.2 mS cm(-1) (E.C.3). Pots containing lettuce plants were first inoculated with F. oxysporum f. sp. lactucae (3x10(5) chlamidospores ml(-1)) 15-20 days before transplanting. Disease severity and physiological parameters, including chlorophyll content, were analyzed weekly after transplanting. The addition of potassium silicate slightly reduced Fusarium wilt, at all levels of electrical conductivity under study, compared to the control. On the contrary, the increase of electrical conductivity of the nutrient solution showed no effect on the disease. The use of silicon was previously demonstrated to significantly reduce downy mildew on lettuce in soilless systems, and in this trial it demonstrated to slightly reduce disease severity of an important soil-borne pathogen like F. oxysporum f. sp. lactucae, suggesting the possibility to apply it successfully in soilless crops.

Phytophthora capsici: A Soilborne Pathogen Dangerous on Grafted Tomato (Solanum lycopersicum × S. hirsutum) in Italy

During an extensive survey carried out in Piedmont (northern Italy) aimed at identifying the emerging soilborne diseases affecting tomato in commercial fields where alternatives to methyl bromide have been implemented in response to national and international regulations, sudden collapse of tomato plants, cv. Tomahawk, grafted on cv. Beaufort, were repeatedly observed in a commercial plastic tunnel operation. Affected plants suddenly collapsed 60 days after transplant during the month of May 2010. Symptoms included chlorosis, stunting, and severe root and crown rot, leading to sudden collapse of approximately 25% of the plants within 60 days of transplant. Symptomatic tissues from the root and collar of infected plants were surface disinfested for 1 min in a 1% NaOCl solution, rinsed for 5 min in water, and submerged in selective medium based on corn meal agar. A Phytophthora-like organism (2) with characteristic coenocytic hyphae was consistently isolated and transferred to V8 agar. The sporangia were spherical to ovoid, papillate, and 40 to 77 × 23 to 34 (average 55.1 × 30.3) μm. Oospores were globose and 22.2 to 30.8 μm. The internal transcribed spacer (ITS) region of rDNA of a single isolate was amplified using the primers ITS1/ITS4 and sequenced. BLAST analysis (1) of the 750-bp segment showed a 100% homology with the sequence of Phytophthora capsici JN382543.1. The nucleotide sequence has been assigned the GenBank Accession No. JX090306. Pathogenicity tests were performed on healthy 30-day-old tomato plants cv. Beaufort by using one strain of P. capsici grown for 15 days at 22 to 25°C on a mixture of 2:1 wheat/hemp kernels, and then 1 g per L of the inoculum was mixed into a substrate based on peat blonde/peat black (15:85 v/v). Two plants were transplanted into 3-L pots, with five replicates. Ten non-inoculated plants represented the control treatment; the trial was repeated once. All plants were kept in a greenhouse at temperatures ranging from 22 to 25°C. Inoculated plants became chlorotic 7 days after inoculation and root and crown rot developed 30 days after inoculation. Control plants remained symptomless. P. capsici consistently was reisolated from inoculated plants. In Italy, the presence of P. nicotianae on hybrids of Solanum lycopersicum × S. hirsutum is known (3), while, to the best of our knowledge, this is the first report of P. capsici on the hybrid S. lycopersicum × S. hirsutum in Italy. The economic importance of the disease can increase due to the expanding use of grafted tomato plants. References: (1) S. F. Altschul et al. Nucleic Acids Res. 25:3389, 1997 (2) D. C. Erwin and O. K. Ribeiro. Phytophthora Diseases Worldwide. APS Press, St Paul, MN, 1996. (3) A. Garibaldi and M. L. Gullino. Acta Hortic. 833:35, 2010. (4) H. M. Masago et al. Phytopathology 67:425, 1977.

First Report of Plectosphaerella cucumerina on Greenhouse Cultured Wild Rocket (Diplotaxis tenuifolia) in Italy

During spring 2012, symptoms of an unusual leaf spot disease were observed in several commercial greenhouses near Salerno (southern Italy) on plants of Diplotaxis tenuifolia (cv Selvatica). The first symptoms on leaves of affected plants consisted of small (1 mm) black-brown spots of irregular shape, later coalescing into larger spots, 1 cm in diameter. Spots were surrounded by a yellow halo, and were mostly located on the foliar limb, rib, and petiole. Affected leaves were often distorted, appearing hook-like. The disease was severe under 75 to 90% RH, at air temperature of 20 to 26°C, and caused severe production losses on about 50 ha. Particularly, affected tissues rotted quickly after packaging and during transit and commercialization of processed rocket. Diseased tissue was excised, immersed in a solution containing 1% sodium hypochlorite for 60 s, rinsed in water, then placed on potato dextrose agar (PDA) medium, containing 25 mg/l of streptomycin sulphate. After 5 days, a fungus developed producing a whitish-orange mycelium when incubated under 12 h/day of fluorescent light at 22°C. The isolates obtained were purified on PDA. On this medium, they produced hyaline elliptical and ovoid conidia, sometimes one-septate, measuring 4.5 to 9.2 × 1.7 to 3.5 (average 6.8 × 2.6) μm. Conidia were born on phialides, measuring 6.8 to 20.2 × 1.3 to 3.1 (average 16.5 × 2.1) μm. Such characteristics are typical of Plectosphaerella sp. (2). The internal transcribed spacer (ITS) region of rDNA was amplified using the primers ITS1/ITS4 (3) and sequenced. BLAST analysis of the 519-bp segment showed a 98% similarity with the sequence of Plectosphaerella cucumerina (GenBank Accession No. AB469880). The nucleotide sequence has been assigned the GenBank Accession JX185769. To confirm pathogenicity, tests were conducted on 45-day-old D. tenuifolia plants. Plants (21/treatment), grown in 15 liter pots (7 plants/pot) were inoculated by spraying a 1 × 10⁶ CFU/ml conidial suspension of one isolate of P. cucumerina, prepared from 10-day-old cultures, grown on PDA. Inoculated plants were maintained in a growth chamber at 23 ± 1°C, at 90% RH for 4 days. Non-inoculated plants served as control. Inoculated plants showed the typical first leaf spots 6 days after the artificial inoculation. Four days later, spots enlarged and leaves became distorted, showing chlorosis. Non-inoculated plants remained healthy. P. cucumerina was reisolated from inoculated plants. The pathogenicity test was conducted twice with identical results. This is, to our knowledge, the first report of P. cucumerina on D. tenuifolia in Italy as well as worldwide. P. cucumerina has been described as associated with root and collar rots of other horticultural crops in southern Italy (1). Due to the importance of the crop in Italy, this disease can cause serious economic losses. References: (1) A. Carlucci et al., Persoonia, 28:34, 2012. (2) M. E. Palm et al. Mycologia, 87:397, 1995. (3) T. J. White et al. PCR Protocols: A Guide to Methods and Applications. M. A. Innis et al., eds. Academic Press, San Diego, 1990.

First Report of Leaf Spot of Lettuce (Lactuca sativa L.) Caused by Phoma tropica in Italy

Lettuce (Lactuca sativa L.) is widely grown in Italy, with the production for the preparation of ready-to-eat salads becoming increasingly important. During the spring of 2011, a previously unknown leaf spot was observed on L. sativa plants, cv Rubia, grown in several plastic tunnels in Lumbardy (northern Italy), 20 to 25 days after sowing. Thirty to forty per cent of leaves of the plants growing in the part of the tunnel with the highest relative humidity were affected. Leaves of infected plants showed extensive, irregular, dark brown, necrotic lesions with a chlorotic halo. Lesions initially ranged from 0.5 to 3 mm, then eventually coalesced, reaching 2 to 3 cm, showing a well-defined, dark brown border. Affected leaves senesced and withered. The crown was not affected by the disease. Diseased tissue was excised, immersed in a solution containing 1% sodium hypochlorite for 60 s, rinsed in water, then cultured on potato dextrose agar (PDA), amended with 25 mg/l of streptomycin sulphate. After 5 days, a fungus developed, producing a greenish grey mycelium with a white border when incubated under 12 h/day of fluorescent light at 21 to 23°C. In order to favor the production of conidia, the fungus was transferred on malt extract agar (MA) and maintained under 12 h/day of fluorescent light at 22°C. After 15 days, black pycnidia, 175 to 225 μm, developed, with hyaline, elliptical, unicellular conidia, measuring 3.21 to 6.7 × 1.08 to 3.2 (average 5.5 × 1.9) μm. On the basis of these morphological characteristics, the fungal causal agent of the disease could be related to the genus Phoma (2). The internal transcribed spacer (ITS) region of rDNA of the isolate PHT30 was amplified using the primers ITS1/ITS4 and sequenced. BLAST analysis (1) of the 466-bp segment showed a 99% similarity with the sequence of Phoma tropica (GenBank Accession No. JF923820.1). The nucleotide sequence has been assigned the GenBank Accession No. JQ954396. Pathogenicity tests were performed by spraying healthy 20-day-old lettuce plants, cv Rubia, with a spore suspension (1 × 10⁵ conidia/ml) prepared from 14-day-old colonies of the strain PHT30 grown on MA cultures. Plants inoculated with water alone served as controls. Ten plants per isolate were used. Plants were covered with plastic bags for 5 days after inoculation and maintained in a growth chamber at 20°C and 80% relative humidity. The first foliar lesions, similar to those occurring on the naturally infected plants, developed on leaves 12 days after inoculation. Control plants remained healthy. The pathogen was consistently reisolated from leaf lesions. The pathogenicity test was completed twice. To our knowledge, this is the first report of the presence of P. tropica on lettuce in Italy as well as worldwide. In the United States, the presence of P. exigua was reported in 2006 (3). The economic importance of the disease at present is limited, probably also because symptoms can be confused with those caused by Botrytis cinerea. However, P. tropica could become a more significant problem because of the importance of the crop. References: (1) S. F. Altschul et al. Nucleic Acids Res. 25:3389, 1997. (2) G. H. Boerema. Trans. Br. Mycol. Soc. 67:289, 1976. (3) S. Y. Koike. Plant Dis. 90:1268, 2006.

First Report of Rust Caused by Pucciniastrum circaeae on Fuchsia × hybrida in Italy

Fuchsia is a genus of flowering plants that is native to South America and New Zealand and belongs to the family Onagraceae. In September 2011, 2-year-old potted plants of Fuchsia × hybrida, cv. Citation, in a garden located near Biella (northern Italy) showed signs and symptoms of a previously unknown disease. Typically, infected plants showed leaf chlorosis followed by the appearance of necrosis on the adaxial leaf surfaces, while the abaxial surfaces showed orange uredinia irregularly distributed. As the disease progressed, infected leaves turned yellow and wilted. Affected plants showed a progressive phylloptosis and also flowering was negatively affected. Urediniospores were globose, yellow to orange, and measured 14.6 to 25.9 (average 19.6) μm. Teliospores were not observed. Morphological characteristics of the fungus corresponded to those of the genus Pucciniastrum. DNA extraction and PCR amplification were carried out with Terra PCR Direct Polymerase Mix (Clontech, Saint Germain-en-Laye, France) and primers ITS1/ITS4 (4). A 700-bp PCR product was sequenced and a BLASTn search (1) confirmed that the sequence corresponded with a 96% identity to Pucciniastrum circaeae. The nucleotide sequence has been assigned the GenBank Accession No. JQ029688. Pathogenicity tests were performed by spraying leaves of healthy 1-year-old potted Fuchsia × hybrida plants with an aqueous suspension of 1 × 10³ urediniospores ml^-1. The inoculum was obtained from infected leaves. Plants sprayed only with water served as controls. Three plants were used for each treatment. Plants were covered with plastic bags for 4 days after inoculation and maintained outdoors at temperatures ranging between 18 and 25°C. Lesions developed on leaves 20 days after inoculation with the urediniospore suspension, showing the same symptoms as the original plants, whereas control plants remained healthy. The organism that was recovered from the lesions after inoculation was the same as the one obtained from the diseased plants. The pathogenicity test was carried out twice with similar results. The presence of P. fuchsiae, later identified as P. epilobii, was repeatedly reported in the United States (3). P. epilobii and P. circaeae have closely related hosts and morphologically similar urediniospores. These species were reported to form a single group in molecular phylogenetic trees (2). This is, to our knowledge, the first report of P. circaeae on Fuchsia × hybrida in Italy. References: (1) S. F. Altschul et al. Nucleic Acids Res. 25:3389, 1997 (2) Y. M. Liang et al. Mycoscience 47:137, 2006. (3) L. B. Loring and L. F. Roth. Plant Dis. Rep. 48:99, 1964. (4) T. J. White et al. PCR Protocols: A Guide to Methods and Applications. M. A. Innis et al., eds. Academic Press, San Diego, 1990.

First Report of Leaf Spot of Wild (Diplotaxis tenuifolia) and Cultivated (Eruca vesicaria) Rocket Caused by Alternaria japonica in Italy

Wild (Diplotaxis tenuifolia) and cultivated (Eruca vesicaria) rocket, popular crops in Italy as well as in many Mediterranean areas, are grown for fresh consumption as well as for dish decoration. During fall and winter of 2010 to 2011, extensive necroses were observed on leaves of D. tenuifolia and E. vesicaria that were grown in commercial greenhouses in Piedmont and Liguria (northern Italy). The disease affected 30 to 40% of 60-day-old plants. First symptoms were usually black-brown lesions, 1 to 30 mm in diameter, which progressively turned black. Lesions usually started on the upper side of older leaves at the leaf margins and tips and developed a yellow halo. Eventually, lesions also affected leaf veins and stems. A fungus was consistently isolated from infected leaves on potato dextrose agar and was grown on water agar (15 g/liter) amended with autoclaved rocket tissues (100 g/liter). After 12 days of growth at 22°C and 12-h dark/12-h light, conidia that were produced were dark brown, obclavate, obpyriform, ovoid or ellipsoid, with beaks. Round conidia without beaks were also present. Conidia showed two to seven (average three to four) transverse and one to three longitudinal septa, and measured 17.7 to 56.2 (average 30.9) × 6.6 to 17.8 (average 10.8) μm. Conidia were produced singly or in short chains (two to three elements) and mostly presented a conical or cylindrical beak, 1.8 to 7.3 (average 3.6) μm, pale light brown to brown. On the basis of its morphological characteristics, the pathogen was identified as an Alternaria sp. (3). DNA was extracted with Terra PCR Direct Polymerase Mix (Clontech, Mountain View, CA) and PCR was carried out with ITS 1/ ITS 4 primer (4). A 553-bp PCR product was sequenced and a BLASTn search (1) confirmed that the sequence corresponded to Alternaria japonica. The nucleotide sequence has been assigned the GenBank Accession No. JP 742643. Pathogenicity tests were performed by spraying leaves of healthy 30-day-old wild and cultivated rocket plants with an aqueous 1 × 10⁵ spore/ml suspension. The inoculum was obtained from cultures of the fungus grown on sterilized host leaves placed on water agar for 20 days in light/dark at 22 ± 1°C. Plants sprayed only with water served as controls. Three pots (four plants per pot) were used for each treatment. Plants were covered with plastic bags for 4 days after inoculation and maintained in a glasshouse at 22 ± 1°C. Lesions developed on leaves 7 days after inoculation with the spore suspension, whereas control plants remained healthy. A. japonica was consistently reisolated from these lesions. The pathogenicity test was carried out twice. The presence of A. japonica has been reported on several brassica hosts, such as Brassica napus, B. nigra, B. oleracea, and B. rapa (2). This is, to our knowledge, the first report of A. japonica on wild and cultivated rocket in Italy as well as in Europe. Because of the importance of rocket in many countries, the potential impact of this disease is high. References: (1) S. F. Altschul et al. Nucleic Acids Res. 25:3389, 1997 (2) J. C. David, IMI Description of Fungi and Bacteria. 144:1432, 2000. (3) E. G. Simmons. Alternaria. An Identification Manual. CBS Biodiversity Series 6, Utrecht, The Netherlands, 2007. (4) T. J. White et al. In: PCR Protocols: A Guide to Methods and Applications. M. A. Innis et al., eds. Academic Press, San Diego, 1990.

First Report of Leaf Spot of Rocket (Eruca sativa) Caused by Fusarium equiseti in Italy

During the summer of 2010, rocket (Eruca sativa) plants grown in an open field and under a plastic tunnel in Piedmont (northern Italy) showed symptoms of a previously reported foliar disease. Symptoms were observed on 30-day-old plants and consisted of small, circular, brown leaf spots (1 to 3 to 10 to 12 mm in diameter), sometimes later becoming elliptical. Necrotic lesions were cracked in the center and showed a well-defined border, frequently surrounded by a violet-brown halo. Approximately 40% of the plants were affected with 30 to 40% of the leaves infected. An orange-brown colony with characteristics of Fusarium was isolated from leaf tissues of 30 infected plants on potato dextrose agar (PDA). Isolates were purified, subcultured on PDA, and single-spore cultures were obtained. On PDA, they produced orange-brown colonies and purple pigments. On Spezieller Nährstoffarmer agar (SNA) (1), the isolates produced hyaline macroconidia with dorsiventral curvature, five to seven septate, and measuring 36.2 to 49.3 × 3.4 to 5.3 (average 41.9 × 4.0) μm. Chlamydospores, solitary but also in short chains (two to three elements), measuring 7.2 to 15.3 (average 10.1) μm were produced on carnation leaf agar (CLA) after 10 days and became verrucose 20 days later. Macroconidia were produced on CLA in orange sporodochia from monophialides on branched conidiophores. Microconidia were not observed. Such characteristics are typical of the genus Fusarium (1). The rDNA ITS region (internal transcribed spacer) was amplified using the primers ITS1/ITS4 (2) and sequenced. BLASTn analysis of the 480-bp product obtained showed an E-value of 0.0 with Fusarium equiseti. The nucleotide sequence has been assigned the GenBank Accession No. JF460797. The translation elongation factor-1α (EF-1α) gene (GenBank Accession No. JN127347) was amplified using primers EF-1/EF-2 and sequenced. The 702-bp fragment showed 99% identity with F. equiseti (GenBank Accession No. FJ939673.1). To confirm pathogenicity, 20-day-old rocket plants were transplanted into 2-liter volume pots, filled with a steamed peat/perlite/sand (60:20:20 vol/vol) substrate and maintained in a growth chamber at 25 ± 1°C. Five pots per treatment were used, each pot containing two plants. The artificial inoculation was carried out either by spraying leaves with a spore suspension prepared from 15-day-old cultures of the pathogen on PDA or by applying CLA agar disks (6 mm in diameter) from 10-day-old cultures onto leaves. Control plants were inoculated with distilled water or with noninoculated agar disks. Plants were covered with plastic bags for 5 days. The first symptoms, consisting of chlorotic leaf halo and leaf spots surrounded by a violet-brown halo, developed 15 days after inoculation by foliar spraying and 5 days after inoculation by disks. Noninoculated plants remained healthy. F. equiseti was consistently isolated from symptomatic plants. The pathogenicity test was conducted twice. To our knowledge, this is the first report of F. equiseti on E. sativa in Italy. Currently, this disease is present in several farms in northern Italy. Its importance might increase because of the widespread cultivation of cultivated rocket in Italy. References: (1) J. F. Leslie and B. A. Summerell. The Fusarium Laboratory Manual. Blackwell, Ames, IA, 2006. (2) T. J. White et al. PCR Protocols: A Guide to Methods and Applications. M. A. Innis et al., eds. Academic Press, San Diego, 1990.

First Report of Fusarium Wilt of Chicory (Cichorium intybus) Caused by Fusarium oxysporum in Italy

In the summer of 2009, a wilt of chicory was observed on 25 to 30% of 30-day-old Cichorium intybus L. cv. Clio plants grown outdoors on a commercial farm in Piedmont (northern Italy). Affected plants were chlorotic and stunted with poorly developed root systems compared with healthy plants. Black streaks were observed in the stem and proximal part of the leaf vascular system in wilted plants. Fusarium oxysporum Schltdl. was isolated from symptomatic vascular tissue on a Fusarium-selective medium (1) from 80% of samples. Grown on potato dextrose agar (PDA) for 4 days at 23°C, the colonies, initially white and later pale pink, produced hyaline microconidia that were oval-elliptical and cylindrical in shape measuring 5.6 to 14.9 (average 10.2) × 2.1 to 4.5 (3.0) μm, borne on short monophialides measuring 8.2 to 16.1 (average 13.2) × 2.1 to 4.2 (3.3) μm. Macroconidia were slightly curved, three-septate, with a slightly hooked apical cell and a foot-shaped basal cell measuring 24.9 to 41.6 (average 32.2) × 3.2 to 5.2 (4.3) μm. Chlamydospores were both terminally and intercalary, solitary but also in short chains (2 to 4 elements) measuring 21.1 to 41.0 (average 27.2) μm (2). The internal transcribed spacer (ITS) rDNA region was amplified using the primers ITS1/ITS4 and sequenced. BLASTn analysis of the 527-bp amplicon (GenBank Accession No. HQ644423) obtained had 98% sequence identity with F. oxysporum (GenBank Accession No. FJ605247). The translation elongation factor-1α (EF-1α) gene was amplified using primers EF-1/EF-2 and sequenced (GenBank Accession No. GU564259). The 663-bp fragment had 99% sequence identity with F. oxysporum (GenBank Accession Nos. EU313540, EU313539, and DQ837696). Pathogenicity tests were conducted on 15-day-old chicory plants from two cultivars (Clio and Katia). Thirty-five plants per cultivar were inoculated by dipping their roots in a 1 × 10⁶ CFU/ml suspension of isolate FusCic45B recovered from wilted chicory. Inoculated and noninoculated plants were transplanted into five pots filled with 10 liters of steamed mix (peat/perlite/sand, 60:20:20 vol/vol) and were maintained in a glasshouse at 25 to 27°C. Wilt symptoms and vascular discoloration of the roots, crown, and veins developed 15 days after inoculation on all inoculated plants. Plants of cv. Clio were more susceptible. F. oxysporum was always reisolated from infected plants using the Fusarium-selective medium. All noninoculated plants remained healthy. The pathogenicity test was conducted twice. To our knowledge, this is the first report of wilt caused by F. oxysporum on chicory, C. intybus, in Italy as well as worldwide. References: (1) H. Komada. Rev. Plant Prot. Res. 8:114, 1975. (2) E. Nelson et al. Fusarium Species: An Illustrated Manual for Identification. The Pennsylvania State University Press, University Park, 1983.

First Report of Collar and Root Rot Caused by Phytophthora tentaculata on Witloof Chicory (Cichorium intybus) in Italy

Witloof chicory (Cichorium intybus L.) is an important crop in Italy where most of the crop is still produced in soil. In September 2009, chicory plants (cv. Pan di Zucchero) grown on a commercial farm in Tarquinia (central Italy) showed symptoms of a previously unknown disease. Symptoms, observed 20 days after transplanting, consisted of stunting, yellowing of leaves, and a crown and root rot. Affected plants turned brown, wilted, and eventually died. At the soil level, dark brown-to-black water-soaked lesions coalesced and often girdled the stem. All of the crown and root system was affected. At this location, the disease was severe and widespread, with 60% of observed plants being affected. A Phytophthora-like organism was consistently isolated on a medium selective for oomycetes (4) after disinfestation of lower stem and root pieces of C. intybus for 1 min in a solution containing 1% NaOCl. Tissue fragments of 1 mm² were excised from the margins of the root and crown lesions. The pathogen genus was identified as Phytophthora based on morphological and physiological features. Sporangia were produced for identification by growing a pure culture for 15 days on modified V8 juice agar medium (Campbell V8 juice [200 ml], agar [15 g], CaCo₃ [0.5 g], and sterile water [800 ml]) under alternating light and dark (12/12 h). Sporangia were pyriform to ovoid, papillate, and measured 33.3 to 59.2 × 18.9 to 30.2 μm (average 39.9 × 25.8 μm). Chlamydospores developed in 28-day-old cultures and measured 21.3 to 30.2 × 19.5 to 29.7 μm (average 24.4 × 23.6 μm). Oogonia were globose and measured 26 to 41 μm (average 32.5 μm). Eighty percent of antheridia were paragynous. Amphyginous antheridia (15 to 20%) were also observed. Oospores were scarcely produced and measured 24 to 32 μm in diameter. The internal transcribed spacer (ITS) region of rDNA of a single isolate was amplified using the primers ITS4/ITS6 and sequenced. BLAST analysis (1) of the 851-bp segment showed 100% homology with the sequence of Phytophthora tentaculata. The nucleotide sequence has been assigned GenBank Accession No. GU949536. Pathogenicity of this isolate was confirmed by inoculating C. intybus cv. Pan di Zucchero plants 20 days after transplant. The same isolate was grown for 15 days on a mixture of 70:30 wheat/hemp kernels and then 5 g/liter of the inoculum was mixed into a substrate containing a mixture of blond and black peat (15:85 vol/vol), pH 5.5. Five plants per 2-liter pot were transplanted and four replicates were carried out. Twenty noninoculated plants represented the control treatment. The trial was repeated. Plants were kept in two growth chambers at two temperatures (20 and 25°C). Symptoms similar to those observed in the field developed 7 days after inoculation. Twenty days later, 100 and 40% of the plants were dead at 25 and 20°C, respectively. Control plants remained symptomless. P. tentaculata was consistently reisolated from symptomatic plants. To our knowledge, this is the first report of P. tentaculata on C. intybus in the world ( http://nt.ars-grin.gov/fungaldatabases/index.cfm ). P. tentaculata was recently reported on lavender in Spain (2) and oregano in Italy (3). The economic importance of this disease is relatively low on most commercial farms. References: (1) S. F. Altschul et al. Nucleic Acids Res. 25:3389, 1997. (2) L. Alvarez et al. Plant Dis. 90:523, 2006. (3) P. Martini et al. Plant Dis. 93:843, 2009. (4) H. Masago et al. Phytopathology 67:425, 1977.

First Report of Collar and Root Rot Caused by Pythium ultimum on Coriander in Italy

Coriander, Coriandrum sativum L., is an annual herb in the family Apiaceae. This plant, native to southern Europe, northern Africa, and southeastern Asia, is used in cooking as well as for medicinal uses. The leaves are commonly referred to as cilantro. In October 2009, severe outbreaks of a previously unknown root rot were observed in a commercial field located in the Alessandria Province (northern Italy) on 20-day-old plants belonging to cv. Comune. Five percent of plants were affected, showing stunting and extensive chlorosis starting on external leaves that eventually wilted. Root systems and collars of diseased plants appeared rotted. In advanced stages, young leaves were affected and the plants eventually collapsed and tissues dried out. Tissue fragments of 1 mm² were excised from the roots of infected plants, dipped in a solution containing 1% sodium hypochlorite, and plated on potato dextrose agar (PDA) and a medium selective for Oomycetes (3). Plates were incubated under constant fluorescent light at 22 ± 1°C for 4 to 5 days. One isolate, grown on V8 medium (vegetable mix, 300 g; agar, 15 g; CaCO₃, 1.5g; and distilled water, 1 liter), and observed under a light microscope showed hyphae generally aseptate, ranging from 1.3 to 6.24 μm in diameter, and produced sporangia consisting of complexes of swollen hyphal branches. Oogonia were globose, smooth, and 20.3 to 33.4 (average 25.4) μm in diameter. Antheridia were monoclinous, extending from immediately below oogonium, and measured 10.8 to 17.8 × 7.6 to 12.7 (average 14.4 × 10.4) μm. Oospores were single, globose, aplerotic and thick walled, and 15.8 to 24.2 (average 17.8) μm in diameter. These morphological characters were used to identify the microorganism as a Pythium sp. (3). The internal transcribed spacer (ITS) region of rDNA of a single isolate was amplified using the primers ITS1/ITS4 (2,4) and sequenced. BLAST analysis (1) of the 874-bp segment showed a 100% homology with the sequence of Pythium ultimum. The nucleotide sequence has been assigned the GenBank Accession No. GU478314. Pathogenicity tests were performed twice on coriander cv. Comune. Plants were grown in 2-liter pots containing a Brill Type 5 substrate (Brill Substrate GmbH & Co. KG, Niedersachsen, Germany) consisting of 15% blond peat, 85% black peat, pH 5.5 to 6, and pasteurized at 80°C for 30 min. The potting mix was infested at a rate of 5 g/liter with wheat and hemp kernels colonized with one strain of P. ultimum. Ten plants (1 plant per pot) were grown in the infested substrate and 10 plants were grown in noninfested substrate. Plants were kept in a growth chamber at 20°C. The first symptoms, consisting of reduced growth and chlorosis, developed within 7 days, while control plants remained healthy. P. ultimum was consistently isolated from the roots. To our knowledge, this is the first report of P. ultimum causing disease of coriander in Italy as well as worldwide. At this time, the economic importance of Pythium rot on coriander in Italy remains unknown. References: (1) S. F. Altschul et al. Nucleic Acids Res. 25:3389, 1997. (2) W. Chen et al. Exp. Mycol.16:22, 1992. (3) T. Watanabe. Pictorial Atlas of Soil and Seed Fungi. CRC Press, Boca Raton, FL, 2002. (4) T. J. White et al. Page 38 in: PCR protocols: A Guide to Methods and Applications. M. A. Innis et al., eds. Academic Press, San Diego, 1990.

First Report of Leaf Blight on Woodland Sage Caused by Rhizoctonia solani AG 1 in Italy

Woodland sage (Salvia nemorosa L.; Lamiaceae) is a hardy herbaceous perennial plant that is easy to grow and propagate and is used in parks and grown as potted plants. During the summer of 2009 in a nursery near Torino in northern Italy, a leaf blight was observed on 30-day-old plants of cv. Blau Koenigin grown in pots under shade. Semicircular, water-soaked lesions developed on leaves just above the soil line at the leaf-petiole junction and later along leaf margins. Lesions expanded along the midvein until the entire leaf was destroyed. Blighted leaves turned brown, withered, and clung to the shoots. No symptoms were observed on the roots. Severely infected plants died. Diseased tissue was disinfested for 10 s in 1% NaOCl, rinsed with sterile water, and plated on potato dextrose agar (PDA) amended with 25 mg/liter of streptomycin sulfate. A fungus with morphological characters of Rhizoctonia solani (3) was consistently recovered. Ten-day-old mycelium grown on PDA at 22 ± 1°C appeared light brown, rather compact, and with radial growth. Sclerotia were irregular and measured between 0.5 and 2 mm. Pairings were made with tester isolates of AG 1, 2, 3, 4, 5, 6, 7, 11, and AG B1. The only successful anastomosis was with tester isolate AG 1 (ATCC 58946). The hyphal diameter at the point of anastomosis was reduced, the anastomosis point was obvious, and cell death of adjacent cells was observed. Results were consistent with other reports on anastomosis reactions (2). The description of sclerotia of the isolate AG1 was typical for subgroup 1A Type 2 (3). The internal transcribed spacer (ITS) region of rDNA was amplified using primers ITS4/ITS6 and sequenced. BLASTn analysis (1) of the 688 bp showed a 100% homology with the sequence of R. solani AG-1A and the nucleotide sequence has been assigned (GenBank Accession No. HM044764). For pathogenicity tests, the inoculum of one isolate of R. solani from the nursery was prepared by growing the pathogen on PDA for 7 days. The foliage of 30-day-old potted plants of S. nemorosa cv. Blau Koenigin was artificially inoculated with an aqueous suspension of PDA and mycelium fragments (1 g per mycelium per plant) prepared from cultures with a blender. Plants were covered with plastic bags for 3 days. Plants inoculated with water and PDA fragments alone served as control treatments. Plants were maintained in a glasshouse at 20 to 25°C. The first symptoms, similar to those observed in the nursery, developed 7 days after foliar inoculation. R. solani was consistently reisolated from infected leaves. Control plants remained healthy. The pathogenicity test was carried out twice with similar results. To our knowledge, this is the first report of leaf blight of S. nemorosa caused by R. solani in Italy as well as worldwide. The importance of the disease is still unknown. References: (1) S. F. Altschul et al. Nucleic Acids Res. 25:3389, 1997. (2) D. E. Carling. Page 35 in: Rhizoctonia Species: Taxonomy, Molecular Biology, Ecology, Pathology and Disease Control. Kluwer Academic Publishers, the Netherlands, 1996. (3) B. Sneh et al. Identification of Rhizoctonia Species. The American Phytopathological Society, St Paul, MN, 1991.

First Report of Leaf Spot Caused by Phoma multirostrata on Fuchsia × hybrida in Italy

Fuchsia × hybrida (Onagraceae) is widely used in gardens and very much appreciated as a potted plant. During the summer of 2008, a severe foliar disease was observed on 1- to 2-year-old plants in several gardens located near Biella (northern Italy). Small necrotic spots were observed on the upper and lower sides of infected leaves. Spots enlarged to form round areas of 2 to 12 mm in diameter and were well defined by a brown-purple margin at temperatures between 15 and 25°C. Severely infected leaves wilted and abscised as disease progressed. The disease occurred on 100% of the plants and at least 30% of the leaf surface was affected. Stems and flowers were not affected by the disease. A fungus was consistently isolated from infected leaves on potato dextrose agar amended with 25 mg/liter of streptomycin. The fungus was grown on leaf extract agar, including 30 g of autoclaved fuchsia leaves per liter, and maintained at 22°C (12-h light, 12-h dark). After 30 days, black pycnidia 150 to 450 μm in diameter developed, releasing abundant hyaline, elliptical, nonseptate conidia measuring 5.6 to 14.3 (10.3) × 1.9 to 5.6 (3.5) μm. On the basis of these morphological characteristics, the fungus was identified as a Phoma sp. (2). The internal transcribed spacer (ITS) region of rDNA of the isolate coded FuHy1 was amplified using primers ITS4/ITS6 (3) and sequenced. BLAST analysis (1) of the 488-bp segment obtained showed an E-value of 0.0 with Phoma multirostrata. The nucleotide sequence has been assigned GenBank Accession No. GU220539. Pathogenicity tests were performed by spraying leaves of healthy 6-month-old potted Fuchsia × hybrida plants with a spore and mycelial suspension (1 × 10⁶ spores or mycelial fragments per milliliter). Noninoculated plants sprayed with water served as controls. Five plants were used for each treatment. Plants were covered with plastic bags for 5 days after inoculation and kept under greenhouse conditions at 20 to 24°C. Symptoms previously described developed on leaves 12 days after inoculation, whereas control plants remained healthy. The fungus was consistently reisolated from the lesions of the inoculated plants. The pathogenicity test was carried out twice. To our knowledge, this is the first report of the presence of P. multirostrata on fuchsia in Italy as well as worldwide. The importance of the disease is still limited in Italy. References: (1) S. F. Altschud et al. Nucleic Acids Res. 25:3389, 1997. (2) G. H. Boerema and G. J. Bollen. Persoonia 8:111, 1975. (3) D. E. L. Cooke and J. M. Duncan. Mycol. Res. 101:667, 1997.

First Report of Fusarium Wilt of Endive (Cichorium endivia) Caused by Fusarium oxysporum in Italy

In the summer of 2007, a wilt of endive (Cichorium endivia) cv. Myrna plants was observed on several commercial farms near Alessandria in northern Italy. Approximately 40% of the plants on each farm were symptomatic. Affected plants were stunted and yellow and their root systems were poorly developed. Basal leaves eventually wilted. Black streaks were observed in the proximal part of the leaf vascular system. Fusarium oxysporum was consistently isolated from symptomatic vascular tissue on a Fusarium-selective medium (1). To confirm identification of the pathogen, the translation elongation factor 1α and the ribosomal DNA intergenic spacer (IGS) region were partially sequenced (2). Genomic DNA was extracted from mycelia growing on potato dextrose agar. Amplification of the EF-1α region generated a sequence of 648 bp; the IGS amplicon was 2,500 bp. The EF-1α sequence (GenBank Accession No GQ398152) was 99% similar to the sequence of a F. oxysporum strain isolated from soil and a strain pathogenic on cotton plants (GenBank Accession No. EU246574). The IGS sequence (GenBank Accession No GQ398153) was 97% similar to the sequence of a F. oxysporum strain (GenBank Accession No. EF661647). Pathogenicity tests were conducted on 15-day-old endive plants (cv. Myrna). Ten plants were inoculated by dipping their roots in a 1 × 10⁶ CFU/ml suspension of one of the isolates recovered from a wilted endive plant. Inoculated and noninoculated plants were transplanted into pots filled with steamed soil and maintained in a glasshouse at 23 to 28°C. Wilt symptoms and vascular discoloration of the roots, crown, and veins developed 60 days after inoculation. F. oxysporum was consistently reisolated from infected plants. Noninoculated plants remained healthy. The pathogenicity test was conducted twice. To our knowledge, this is the first report of wilt caused by F. oxysporum on endive in Italy. References: (1) H. Komada. Rev. Plant Prot. Res. 8:114, 1975. (2) G. Mbofung et al. Phytopathology 97:87, 2007.

First Report of Leaf Spot Caused by Pseudomonas cichorii on Coreopsis lanceolata in Italy

Coreopsis lanceolata L. (Compositae), an ornamental species grown in parks and gardens, is very much appreciated for its long-lasting flowering period. In August of 2008, pot-grown plants with necrotic leaf lesions were observed in a commercial nursery located near Biella (northern Italy). Lesions were present, especially along the margin of basal leaves, and sometimes had a chlorotic halo. On infected leaves, dark brown necrosis developed. Leaf stalks were sometimes affected. In many cases, the leaves, especially those at collar level, were withered. Of 1,500 plants, 15% were infected by the disease. Microscopic examination did not reveal any fungal structures within the lesions. Small fragments of tissue from 30 affected leaves were macerated for 15 min in casein hydrolysate and 0.1-ml aliquots of the resulting suspension were spread onto Luria Bertani agar (LB) and potato dextrose agar (PDA). Plates were maintained at 22 ± 1°C for 48 h. No fungi were isolated from the leaf spots on LB or PDA. Colonies similar to those of Pseudomonas spp. were consistently isolated on LB. Colonies were fluorescent on King's medium B, levan negative, oxidase positive, potato soft rot negative, arginine dihydrolase negative, and tobacco hypersensitivity positive (LOPAT test). The bacterial colonies were identified as Pseudomonas cichorii (2). The internal transcribed spacer (ITS) region of rDNA was amplified using primers 27F and 1492R and sequenced (GenBank Accession No. FJ534557). BLAST analysis (1) of the 998-bp segment showed a 98% homology with the sequence of P. cichorii. The pathogenicity of one isolate was tested twice by growing the bacterium in nutrient broth shake cultures for 48 h at 20 ± 1°C. The suspension was centrifuged, the cell pellet resuspended in sterile water to a concentration of 10⁷ CFU/ml, and 30 4-month-old healthy coreopsis plants were sprayed with the inoculum. The same number of plants was sprayed with sterile nutrient broth as a control. After inoculation, plants were covered with plastic bags for 48 h and placed in a growth chamber at 20 ± 1°C. Five days after inoculation, lesions similar to those seen in the field were observed on all plants inoculated with the bacterium, but not on the controls. Ten days later, 40% of the leaves were withered. Isolations were made from the lesion margins on LB and the resulting bacterial colonies were again identified as P. cichorii. The pathogen caused the same symptoms also on plants of Dendranthema frutescens (cv. Camilla), Chrysanthemum morifolium (cvs. Eleonora and Captiva), and an Osteospermum sp. (cv. Wild side) when artificially inoculated with the pathogen with the same methodology. The same bacterial leaf spot caused by P. cichorii was observed in 2005 in other nurseries in the same area on Phlox paniculata (3). To our knowledge, this is the first report of bacterial leaf spot caused by P. cichorii on C. lanceolata in Italy. References: (1) S. F. Altschul et al. Nucleic Acids Res. 25:3389, 1997. (2) H. Bergey et al. Bergey's Manual on Determinative Bacteriology. Williams and Wilkins, Baltimore, MD, 1994. (3) A. Garibaldi et al. Plant Dis. 89:912, 2005.

First Report of Leaf Blight on Fan Columbine (Aquilegia flabellata) Caused by Rhizoctonia solani AG 4 in Italy

Aquilegia flabellata (Ranunculaceae), fan columbine, is a perennial herbaceous plant with brilliant blue-purple flowers with white petal tips. It can also be grown for cut flower production. In April of 2008, in several nurseries located near Biella (northern Italy), a leaf blight was observed on 10 to 15% of potted 30-day-old plants grown on a sphagnum peat substrate at 15 to 20°C and relative humidity of 80 to 90%. Semicircular, water-soaked lesions developed on leaves just above the soil line at the leaf-petiole junction and later along the leaf margins. Lesions expanded over several days along the midvein until the entire leaf was destroyed. Blighted leaves turned brown, withered, and abscised. Severely infected plants died. Diseased tissue was disinfested for 10 s in 1% NaOCl, rinsed with sterile water, and plated on potato dextrose agar (PDA) amended with 25 mg/liter streptomycin sulfate. A fungus with the morphological characteristics of Rhizoctonia solani was consistently recovered, then transferred and maintained in pure culture. Ten-day-old mycelium grown on PDA at 22 ± 1°C appeared light brown, rather compact, and had radial growth. Sclerotia were not present. Isolates obtained from affected plants successfully anastomosed with tester isolate AG 4 (AG 4 RT 31, obtained from tobacco plants). Results were consistent with other reports on anastomosis reactions (2). Pairings were also made with tester isolates of AG 1, 2.1, 2.2, 3, 6, 7, 11, and BI with no anastomoses observed between the recovered and tester isolates. The internal transcribed spacer (ITS) region of rDNA was amplified using primers ITS4/ITS6 and sequenced. BLASTn analysis (1) of the 648-bp fragment showed a 100% homology with the sequence of R. solani AG-4 AB000018. The nucleotide sequence has been assigned GenBank Accession No. FJ 534555. For pathogenicity tests, the inoculum of R. solani was prepared by growing the pathogen on PDA for 10 days. Five plants of 30-day-old A. flabellata were grown in 3-liter pots. Inoculum consisting of an aqueous suspension of PDA and mycelium disks (5 g of mycelium + agar per plant) was placed at the collar of plants. Five plants inoculated with water and PDA fragments alone served as control treatments. Plants were maintained in a greenhouse at temperatures between 20 and 24°C. The first symptoms, similar to those observed in the nursery, developed 7 days after the artificial inoculation. R. solani was consistently reisolated from infected leaves and stems. Control plants remained healthy. The pathogenicity test was carried out twice with similar results. The presence of R. solani AG1-IB on A. flabellata has been reported in Japan (4), while in the United States, Rhizoctonia sp. is described on Aquilegia sp. (3). This is, to our knowledge, the first report of leaf blight of A. flabellata caused by R. solani in Italy as well as in Europe. References: (1) S. F. Altschul et al. Nucleic Acids Res. 25:3389, 1997. (2) D. E. Carling. Grouping in Rhizoctonia solani by hyphal anastomosis reactions. In: Rhizoctonia Species: Taxonomy, Molecular Biology, Ecology, Pathology and Disease Control. Kluwer Academic Publishers, The Netherlands, 1996. (3) D. F. Farr et al. Fungi on Plants and Products in the United States. The American Phytopathological Society, St Paul, MN, 1989. (4) E. Imaizumi et al. J. Gen. Plant Pathol. 66:210, 2000.

Report of Leaf Blight on Washington Lupine (Lupinus polyphyllus) Caused by Rhizoctonia solani AG 4 in Italy

Lupinus polyphyllus (Leguminosae), Washington lupine, is a perennial herbaceous plant. In March 2008, in a campus greenhouse at the University of Torino, Grugliasco (northern Italy), a leaf blight was observed on 20% of potted 30-day-old plants. Semicircular, water-soaked lesions developed on leaves just above the soil line at the leaf-petiole junction and later along the leaf margins. Lesions expanded for several days along the midvein until the entire leaf was destroyed. Blighted leaves turned brown, withered, clung to the shoots, and matted on the surrounding foliage. Severely infected plants died. Plants were grown in a sphagnum peat/perlite/clay (70:20:10) substrate at temperatures between 18 and 25°C and relative humidity of 60 to 80%. Diseased tissue was disinfested for 10 s in 1% NaOCl, rinsed with sterile water, and plated on potato dextrose agar (PDA) amended with 25 mg/liter of streptomycin sulfate. A fungus with the morphological characteristics of Rhizoctonia solani (4) was consistently and readily recovered, then transferred and maintained in pure culture. Ten-day-old mycelium grown on PDA at 20 ± 1°C appeared light brown, rather compact, and exhibited radial growth. The isolates of R. solani successfully anastomosed with tester isolate AG 4 (AG 4 RT 31, obtained from tobacco plants). The hyphal diameter at the point of anastomosis was reduced, the anastomosis point was obvious, and cell death of adjacent cells was observed. Results were consistent with other reports on anastomosis reactions (3). Pairings were also made with tester isolates AG 1, 2.1, 2.2, 3, 6, 7, 11, and BI with no anastomoses observed between the recovered and tester isolates. The internal transcribed spacer (ITS) region of rDNA was amplified using primers ITS4/ITS6 and sequenced. BLASTn analysis (1) of the 660-bp fragment showed 100% homology with the sequence of R. solani. The nucleotide sequence has been assigned GenBank Accession No. FJ486272. For pathogenicity tests, the inoculum of R. solani was prepared by growing the pathogen on PDA for 10 days. Plants of 30-day-old L. polyphyllus were grown in 10-liter containers (10 plants per container) on a steam disinfested sphagnum peat/perlite/clay (70:20:10) medium. Inoculum, consisting of an aqueous suspension of mycelium disks prepared from PDA cultures (5 g of mycelium per plant), was placed at the collar of plants. Plants inoculated with water and PDA fragments alone served as control treatments. Three replicates were used. Plants were maintained in a greenhouse at temperatures between 18 and 23°C. First symptoms, similar to those observed in the nursery, developed 10 days after the artificial inoculation. R. solani was consistently reisolated from infected leaves and stems. Control plants remained healthy. The pathogenicity test was repeated twice. The susceptibility of L. polyphyllus to R. solani was reported in Poland (2). This is, to our knowledge, the first report of leaf blight of L. polyphyllus caused by R. solani in Italy. The importance of the disease is at the moment limited. References: (1) S. F. Altschul et al. Nucleic Acids Res. 25:3389, 1997. (2) W. Blaszczak. Rocz. Nauk. Roln. Ser A 85:705, 1962. (3) D. E. Carling. Grouping in Rhizoctonia solani by hyphal anastomosis reactions. In: Rhizoctonia Species: Taxonomy, Molecular Biology, Ecology, Pathology and Disease Control. Kluwer Academic Publishers, The Netherlands, 1996. (4) B. Sneh et al. Identification of Rhizoctonia species. The American Phytopathological Society, St Paul, MN, 1991.

First Report of Leaf Blight on Foxglove (Digitalis purpurea) Caused by Rhizoctonia solani AG-1-IA in Italy

Digitalis purpurea (Scrophulariaceae), foxglove, is used in flower gardens. In the spring of 2008, leaf blight was observed in a nursery near Biella (northern Italy) on 30% of potted 30-day-old plants grown in a peat substrate at temperatures from 20 to 25°C and relative humidity at 75 to 80%. Semicircular, water-soaked lesions developed on leaves just above the soil line at the blade-petiole junction and later along the leaf margins. Lesions expanded for several days along the midvein until the entire leaf was affected. Blighted leaves turned brown, withered, clung to the shoots, and matted on the surrounding foliage. Diseased tissue was disinfested for 10 s in 1% NaOCl, rinsed with sterile water, and plated on potato dextrose agar (PDA) amended with 100 mg/liter of streptomycin sulfate. A fungus with the morphological characteristics of Rhizoctonia solani was consistently and readily recovered, then transferred and maintained in pure culture (4). The isolates of R. solani obtained from affected plants successfully anastomosed with tester isolate AG 1 (ATCC 58946). The hyphal diameter at the point of anastomosis was reduced, the anastomosis point was obvious, and cell death of adjacent cells was observed. Results were consistent with other reports on anastomosis reactions (2). Pairings were also made with tester isolates AG 2, 3, 4, 6, 7, 11, and AG BI and anastomosis was not observed. Ten-day-old colonies grown on PDA appeared light brown, rather compact, and radial. Numerous sclerotia of uniform size (0.5 to 3 mm in diameter) and sometimes joined laterally were formed. Descriptions of mycelium and sclerotia were typical for subgroup IA Type 2 (4). The internal transcribed spacer (ITS) region of rDNA was amplified using primers ITS4/ITS6 and sequenced. BLASTn analysis (1) of the 724-bp fragment showed a 99% homology with the sequence of R. solani (GenBank Accession No. EU591800). The nucleotide sequence has been assigned GenBank Accession No. FJ467490. For pathogenicity tests, the inoculum of R. solani was prepared by growing the pathogen on PDA for 10 days. Plants of 30-day-old D. purpurea were grown in 10-liter containers (6 plants per container) in a steam disinfested peat/clay/perlite (70:20:10) substrate. Disks of PDA cultures were placed on leaves (1 cm² of mycelium per plant). Plants inoculated with PDA alone served as control treatments. Three replicates were used. Plants were maintained in a growth chamber at 24 ± 1°C with 12 h light/dark. First symptoms developed 12 days after the artificial inoculation. R. solani was consistently reisolated from infected leaves and stems. Control plants remained healthy. The pathogenicity test was repeated twice. R. solani was isolated from a small percentage of infected seeds of D. purpurea in India (3). This is, to our knowledge, the first report of leaf blight of D. purpurea caused by R. solani in Italy as well as in Europe. The spread of R. solani in nurseries might cause a decrease in trade. References: (1) S. F. Altschul et al. Nucleic Acids Res. 25:3389, 1997. (2) D. E. Carling. Grouping in Rhizoctonia solani by hyphal anastomosis reactions in: Rhizoctonia Species: Taxonomy, Molecular Biology, Ecology, Pathology and Disease Control. Kluwer Academic Publishers, the Netherlands, 1996. (3) K. K. Janardhanan and D. Ganguly. Indian Phytopathol. 16:379, 1963. (4) B. Sneh et al. Identification of Rhizoctonia Species. The American Phytopathological Society, St Paul, MN, 1991.

Chemical control of downy mildew on lettuce and basil under greenhouse

Eight experimental trials were carried out during 2007 and 2008 to evaluate the efficacy of different fungicides against downy mildew of lettuce (Bremia lactucae) and basil (Peronospora belbahrii) under greenhouse conditions, at temperatures ranging from 19 to 24 degrees C. The mixture fluopicolide (fungicide belonging to the + propamocarb hydrochloride (fungicide belonging to the new chemical class of acyl-picolides) was compared with metalaxyl m + copper, zoxamide + mancozeb, iprovalicarb + Cu, fenamidone + fosetyl-Al and azoxystrobin. Two treatments were carried out at 8-12 day interval on lettuce and basil. The artificial inoculation of B. lactucae on lettuce (cv Cobham Green) and P. belbahrii. on basil (cv Genovese gigante) was carried out by using 1 x 10(5) CFU/ml 24 h after the first treatment. In the presence of a medium-high disease severity, all fungicides tested in these trials were effective against downy mildew on lettuce and basil as the other fungicides already available. The importance of the availability of a number of different chemicals to control downy mildews is discussed.

Attempts to control Fusarium root rot of bean by seed dressing

In summer 2006, a root rot caused by Fusarium oxysporum was observed in commercial farms on common bean (Phaseolus vulgaris) on the cv Billò and Borlotto. A study was undertaken in order to evaluate the efficacy of different biological control agents applied as seed dressing. In the presence of a medium-high disease incidence, among the biocontrol agents tested, Trichoderma harzianum T 22, Bacillus subtilis QST 713, followed by Pseudomonas chlororaphis, provided generally the best control. Their efficacy was also consistent in the different trials. Also the mixture of T. harzianum + T. viride provide a good disease control. Streptomyces griseoviridis and the 3 strains of Fusarim oxysporum, although less effective, provided a partial control of the disease. The fungicide mancozeb provided only a partial disease control.

First Report of Powdery Mildew Caused by Podosphaera xanthii on Calendula officinalis in Italy

Calendula officinalis L. (Asteraceae) (pot marigold or English marigold) is an ornamental species grown in gardens and as potted plants for the production of cut flower. It was also used in ancient Greek, Roman, Arabic, and Indian cultures as a medicinal herb as well as a dye for fabrics, foods, and cosmetics. During the summer of 2007, severe outbreaks of a previously unknown powdery mildew were observed on plants in several gardens near Biella (northern Italy). Both surfaces of leaves of infected plants were covered with dense, white mycelia and conidia. As the disease progressed, infected leaves turned yellow and died. Mycelia and conidia also were observed on stems and flower calyxes. Conidia were hyaline, ellipsoid, born in short chains (four to six conidia per chain), and measured 27.0 to 32.1 (31.4) × 12.9 to 18.4 (18.2) μm. Conidiophores measured 49 to 77.3 (67.2) × 8 to 13.3 (10.8) μm and showed a foot cell measuring 44 to 59 (51.9) × 9.3 to 12.6 (11.3) μm followed by one shorter cell measuring 15.6 to 18.9 (17.6) × 10.4 to 13.6 (12.2) μm. Fibrosin bodies were present. Chasmothecia were spherical, amber colored, with a diameter of 89 to 100 (94.5) μm. Each chasmothecium contained one ascus with eight ascospores. On the basis of its morphology, the causal agent was determined to be a Podosphaera sp. (2). The internal transcribed spacer (ITS) region of rDNA was amplified using the primers ITS4/ITS6 and sequenced. BLASTn analysis (1) of the 588 bp showed a 100% homology with the sequence of Podosphaera xanthii (2). The nucleotide sequence has been assigned GenBank Accession No. EU100973. Pathogenicity was confirmed through inoculations by gently pressing diseased leaves onto leaves of healthy C. officinalis plants. Five plants were inoculated. Five noninoculated plants served as control. Plants were maintained in a greenhouse at temperatures ranging from 20 to 26°C. Eleven days after inoculation, typical symptoms of powdery mildew developed on inoculated plants. Noninoculated plants did not show symptoms. The pathogenicity test was carried out twice. To our knowledge, this is the first report of powdery mildew on C. officinalis in Italy. C. officinalis was previously described as a host to Sphaerotheca fuliginea (synonym S. fusca) in Great Britain (4) as well as in Romania (3). Voucher specimens are available at the AGROINNOVA Collection, University of Torino. References: (1) S. F. Altschul et al. Nucleic Acids Res. 25:3389, 1997. (2) U. Braun and S. Takamatsu. Schlechtendalia 4:1, 2000. (3) E. Eliade. Rev. Appl. Mycol. 39:710, 1960. (4) F. J. Moore. Rev. Appl. Mycol. 32:380, 1953.

Effect of fungicides and of biocontrol agents against powdery mildew of turnip

The activity of several fungicides and of two biocontrol agents, Bacillus subtilis and Ampelomyces quisqualis, alone and in combination, against Erysiphe cruciferarum, causal agent of powdery mildew, was evaluated on turnip under controlled conditions. Among the tested fungicides, quinoxyfen and azoxystrobin provided the best disease control, followed by penconazole, myclobutanil, dinocap and meptyldinocap. Sulphur provided a only partial control. The two biocontrol agents used alone provided a only partial disease control, with B. subtilis being generally more effective. The mixture B. subtilis + azoxystrobin was very effective and generally more active than the two components applied alone. The possibility of introducing biocontrol agents into IPM is discussed.

First Report of Leaf Spot and Root Rot Caused by Phoma betae on Beta vulgaris subsp. vulgaris (Garden Beet Group) in Italy

In the winter of 2007 in Piedmont (northern Italy), symptoms of a previously unknown disease were observed on beet (Beta vulgaris L. subsp. vulgaris) (garden beet group) grown under a tunnel on several commercial farms near Cuneo. First symptoms appeared on 1-month-old plants, occurring as brown, round-to-oval spots as much as 2 cm in diameter with dark concentric rings near the perimeter. Small, dark pycnidia were present throughout the spots in concentric rings. Generally, older, lower leaves were affected more than the younger ones. Ten to fifteen percent of the plants were affected. Symptoms on the roots began near the crown as small, dark, sunken spots that became soft and water soaked. Eventually, spots on the roots turned dark brown to black and black lines separated diseased and healthy tissues. Older infected tissues were black, dry, shrunken, and spongy. Pycnidia were not observed on affected roots. From infected leaves and roots, a fungus was consistently isolated on potato dextrose agar (PDA) amended with 25 mg/l of streptomycin. The fungus was grown on PDA and maintained at 22°C (12 h of light, 12 h of dark). After 10 days, black pycnidia (130 to 328 [204] μm in diameter) developed, releasing abundant hyaline, elliptical, nonseptate conidia measuring 3.9 to 6.7 (5.1) × 2.4 to 5.9 (3.6) μm. On the basis of its morphological characteristics, the fungus was identified as a Phoma sp. (1). The internal transcribed spacer (ITS) region was amplified using primers ITS4/ITS6 (2) and sequenced. BLASTn analysis of the 557 bp obtained showed an E-value of 0.0 with Phoma betae. The nucleotide sequence has been assigned GenBank Accession No. EU003450. Pathogenicity tests were performed by spraying leaves of healthy 20-day-old potted B. vulgaris plants with a spore and mycelial suspension (1 × 10⁶ spores or mycelial fragments per ml). Noninoculated plants sprayed only with water served as controls. Fifteen plants (three per pot) were used for each treatment. Plants were covered with plastic bags for 5 days after inoculation and kept in a growth chamber at 20°C. Symptoms previously described developed on leaves of all inoculated plants 5 days after inoculation, while control plants remained healthy. Later, pycnidia and conidia, with the same dimensions and characteristics previously described, were observed on the infected leaves. The fungus was consistently reisolated from the lesions of the inoculated plants. The pathogenicity test was carried out twice. P. betae on B. vulgaris var. cycla has been reported in Canada (3) as well as in other countries. The same pathogen was reported in Italy on sugar beet (2). References: (1) G. H. Boerema and G. J. Bollen. Persoonia 8:111, 1975. (2) A. Canova. Inf. Fitopatol. 16:207, 1966. (3) D. E L. Cooke and J. M. Duncan. Mycol. Res. 101:667, 1997. (4) J. R. Howard et al. Diseases of Vegetable Crops in Canada. Canadian Phytopathological Society, 1994.

First Report of Leaf Blight on Coral Bells (Heuchera sanguinea) Caused by Rhizoctonia solani AG 1A in Italy

Heuchera sanguinea (Saxifragaceae), coral bells or alum root, is an herbaceous perennial used in parks and gardens and sometimes grown in pots for its heart-shaped leaves and upright panicles of bright red, tiny flowers produced in late spring. At the end of fall 2006, a leaf blight was observed on 50% of a crop of potted 45-day-old plants grown in a sphagnum peat/clay/perlite (70:20:10) substrate at temperatures ranging between 20 and 25°C in a nursery. Semicircular, water-soaked lesions developed on leaves just above the soil line at the leaf-petiole junction and later along the leaf margins. For several days, lesions expanded along the midvein until the entire leaf was destroyed. Blighted leaves turned brown, withered, clung to the shoots, and matted on the surrounding foliage. Mycelia were often seen on and suspended between leaves. Blight progressed up the plant from the leaves to the shoot tip. Affected plants often died leaving wide empty areas. Diseased tissue was disinfected for 1 min in 1% NaOCl, rinsed with sterile water, and plated on potato dextrose agar (PDA) amended with 100 μg/liter of streptomycin sulfate. A fungus with the morphological characters of Rhizoctonia solani was consistently and readily recovered, then transferred and maintained in pure culture (3). The isolates of R. solani obtained from affected plants were successfully anastomosed with tester isolate AG 1 (ATCC 58946). The hyphal diameter at the point of anastomosis was reduced, the anastomosis point was obvious, and cell death of adjacent cells was observed. Results were consistent with other reports on anastomosis reactions (1). Pairings were also made with tester isolates of AG 2, 3, 4, 5, 6, 7, and 11 with no anastomoses observed between the recovered and tester isolates. Sclerotia were of uniform size with a diameter from 0.4 to 4 mm and sometimes joined laterally. The description of sclerotia was typical for subgroup 1A Type 2 (2). For pathogenicity tests, the inoculum of R. solani was prepared by growing three isolates of the pathogen on PDA for 7 days. Plants of 30-day-old H. sanguinea were grown in 10-liter containers (6 plants per container) on a steam disinfested peat/clay/perlite substrate (70:20:10)). Inoculum consisted of an aqueous suspension of PDA and mycelium disks (1 cm² of mycelium per plant) and was placed at the base of the plant stems and on leaves. Plants inoculated with water and PDA fragments alone served as control treatments. Three replicates were used. Plants were maintained in a growth chamber at 24°C with 12 h of light/dark. The first symptoms, similar to those observed in the nursery, developed 12 days after the artificial inoculation. R. solani was consistently reisolated from infected leaves and stems. Control plants remained healthy. The pathogenicity test was carried out twice with similar results. This is, to our knowledge, the first report of leaf blight of H. sanguinea caused by R. solani in Italy and probably in the world. References: (1) D. E. Carling. Grouping in Rhizoctonia solani by hyphal anastomosis reactions. In: Rhizoctonia Species: Taxonomy, Molecular Biology, Ecology, Pathology and Disease control. Kluwer Academic Publishers, the Netherlands, 1996. (2) R. T. Sherwood. Phytopathology, 59:1924, 1969. (3) B. Sneh et al. Identification of Rhizoctonia species. The American Phytopathological Society, St Paul, MN, 1991.

First Report of Verticillium Wilt Caused by Verticillium dahliae on Lettuce in Italy

Lettuce (Lactuca sativa L.) is an important crop used for fresh and processing markets in Italy and is grown on more than 21,000 ha. During October and November of 2006, wilt symptoms were observed on field-grown lettuce, cv. Estelle, in Forlì, Emila Romagna (northeastern Italy) and on cv. Ballerina grown under plastichouses in Piedmont (northwestern Italy). Both lettuce cultivars were of a butterhead type. Affected plants were stunted and developed yellow leaves with brown or black streaks in the vascular tissue. Yellowing started from the external leaves. Discoloration was observed in the vascular tissue of roots, crown, and leaves. A fungus was consistently and readily isolated from symptomatic vascular tissue, previously disinfested in 1% sodium hypochlorite, when cultured on potato dextrose agar (PDA). Microscopic observations revealed hyaline hyphae with many ovoid, dark microsclerotia measuring 32 to 43 × 16 to 26 μm developing after 15 days of growth at 18°C in the dark. Conidiophores showed two verticils of three elements. Conidia were hyaline, elliptical, single celled, and measured 3.5 to 8.5 × 1.8 to 4.3 μm (average 5.5 × 2.5 μm). According to its morphological characteristics, the fungus was identified as Verticillium dahliae (2). Healthy, 20-day-old lettuce plants, cvs. Principessa and Maxima, both belonging to the butterhead type, were separately inoculated by root dip with a conidial suspension (10⁶/ml) of two isolates of V. dahliae isolated, respectively, at Forlì and Torino. Noninoculated lettuce plants served as control treatments. Plants (10 per treatment) were grown in pots (10-liter vol.) in a steam-disinfested peat/perlite/sand (3:1:1 vol/vol) substrate and were maintained in a glasshouse at temperatures ranging between 17 and 22°C and relative humidity ranging between 60 and 70%. First wilt symptoms and vascular discoloration in the roots, crown, and veins developed 40 days after the artificial inoculation. Forty percent of the plants were affected in the case of cv. Maxima and 30% for cv. Principessa. Noninoculated plants remained healthy. The pathogenicity tests were repeated twice. To our knowledge, this is the first report in Italy of Verticillium wilt on lettuce. The disease has been previously reported in Greece (1) and the United States (3). Currently, Verticillium wilt of lettuce seems restricted in Italy to very few farms in the two locations; moreover, its incidence is very low (0.05%). References: (1) E. K. Ligoxigakis et al. Phytoparasitica 30:141, 2002. (2) G. F. Pegg and B. L. Brady. Verticillium Wilts. CABI Publishing, Wallingford, UK, 2002. (3) G. E. Vallad et al. Plant Dis. 89:317, 2005.

First Report of Leaf Spot Caused by Alternaria alternata on Hydrangea macrophylla in Italy

Hydrangea macrophylla is cultivated as an ornamental and also used in the landscape. During the fall of 2005, leaves and young stems on 12-month-old plants (cvs. Hanabi, Nigra, and Zaffiro) grown in pots in several gardens and commercial nurseries in the Piedmont (northern Italy) had extensive necrosis. In many cases, 4-mm-diameter spots on the upper side of the leaves were surrounded by a chlorotic halo, which turned progressively black. Lesions often coalesced into 3- to 8-cm-diameter necrotic areas. Initial necrosis developed mainly on the leaf margins and near the petioles. Severely affected plants were defoliated. Infected plants rarely died, but the presence of lesions reduced the aesthetic quality and subsequently the commercial value. The disease occurred on 30 to 50% of the plants. Leaf spots contained dark brown, multicellular, pear-shaped conidia. Conidia were 19.2 to 36.5 μm (average 26.3 μm) long and 7.7 to 11.5 μm (average 8.9 μm) wide, with 3 to 4 longitudinal cross walls and an average of 4.4 single cells. A fungus identified on the basis of its morphological characteristics as an Alternaria sp. was consistently isolated from symptomatic leaves onto potato dextrose agar. DNA was extracted from mycelium (Nucleospin Plant Kit, Macherey Nagel, Brockville, ON, Canada) and PCR was completed using Alt-for/Alt-rev primers (3), which amplified a part of the gene that encodes for the protein Alt a 1, the major allergen produced by the genus Alternaria. A 305-bp fragment was amplified, sequenced, and the sequence was subjected to BLASTn analysis (1), which confirmed that the isolate belonged to the genus Alternaria and to the alternata group (3). The nucleotide sequence has been deposited in GenBank (Accession No. EF446670). Pathogenicity tests were performed by spraying leaves of healthy potted H. macrophylla plants, cvs. Zaffiro (6-month-old) and Hanabi (12-month-old) with a spore suspension (10⁵ conidia/ml). Plants sprayed with water only served as a control. Ten plants per cultivar were used for each treatment. Plants were covered with plastic bags for 5 days after inoculation and maintained at 20°C for an additional 7 days. Plants were transferred outdoors and kept at temperatures ranging from 19 to 25°C. The first foliar lesions developed on leaves 15 days after inoculation, whereas control plants remained healthy. Alternaria sp. was consistently reisolated from these lesions. The pathogenicity test was completed twice. The presence of Alternaria sp. on Hydrangea spp. was reported in the United States (2), whereas A. hortensiae was observed in Spain (4). To our knowledge, this is the first report of Alternaria sp. belonging to the alternata group infecting H. macrophylla in Italy. The disease is currently spreading in other Italian areas. References: (1) S. F. Altschud et al. Nucleic Acids Res. 25:3389, 1997. (2) M. L. Daughtrey et al. Page 9 in: Compendium of Flowering Potted Plant Diseases. The American Phytopathological Society, St. Paul, MN, 1995. (3) S. Gyu Hong et al. Fungal Genet. Biol. 42:119, 2005. (4) L. M. Unamuno. An. Jard. Bot. Madr. 4:145, 1944.

First Report of Alternaria Leaf Spot on Camellia in Italy

Camellia cultivation has a long history in the Lake Maggiore area of northern Italy where a wide selection of varieties is present. Camellias are appreciated for their large, colorful flowers that bloom from late fall through early spring. In July 2005, a previously unknown foliar disease was observed on a collection of 2- to 12-month-old camellia cultivars (Camellia japonica) grown in several nurseries located in the Verbania Province (northern Italy). The disease was observed on plants grown in pots (10 to 24 cm in diameter) that were maintained either in the open or in a greenhouse and was present for the entire growing season. However, symptoms were more severe during the summer with temperatures ranging between 25 and 30°C with high relative humidity values. During the months of June and July of 2005, severe attacks involving as much as 70% of plants were observed on C. japonica cvs. Mrs. Tingley, Burnside, Hagoromo (synonym Magnoliaeflora), and Giuseppe Traverso. The disease was again observed in 2006. On the upper side of the younger leaves, small necrotic spots (3 to 8 mm in diameter) initially developed mainly at the margin of the leaves and near the petioles. Necrotic areas were surrounded by a chlorotic halo that turned progressively black. The necrotic areas often coalesced, generating larger spots with a diameter ranging from 15 to 30 mm. Severely affected plants were defoliated. Infected plants sometimes died. The presence of lesions on mature plants decreased aesthetic quality and market value. Leaf spots contained dark brown, multicellular, pyriform conidia. Conidia, generally in short chains, were 20.5 to 34.8 μm (average 29.3 μm) long, 6.9 to 12.2 μm (average 9.9 μm) wide, with 3 to 4 longitudinal cross walls, and an average of 5.7 single cells. From 15 samples of infected leaves, several isolates of a fungus identified on the basis of its morphological characteristics as belonging to the Alternaria alternata complex (2) were consistently isolated on potato dextrose agar containing 25 mg/l of streptomycin sulfate. Pathogenicity tests were performed by spraying leaves of healthy 6-month-old potted C. japonica cv. Burnside plants with a spore and mycelial suspension (1 × 10⁵ CFU/ml) prepared by using a mixture of three isolates obtained in 2005 grown on PDA for 30 days at 23 ± 2°C in a growth chamber (12 h of light per day). Plants without inoculation served as a control. Five plants were used for each treatment. Plants were covered with plastic bags for 3 days after inoculation and maintained at 25°C in growth chambers. The first lesions developed on leaves 3 days after inoculation, while control plants remained healthy. Sixty days after artificial inoculation, 25% of the inoculated plants were dead, while the control plants remained healthy. From lesions of infected plants, a fungus belonging to the A. alternata complex was consistently reisolated. The pathogenicity test was carried out twice. The presence of A. alternata on C. sinensis, the commercial tea plant, was reported in India (1). Previously, a flower blight caused by A. tenuis was reported in the United States (3). This is, to our knowledge, the first report of A. alternata on C. japonica in Italy and probably in the world. The disease was present in 2005 and 2006 in several commercial nurseries affecting 50% of plants of susceptible cultivars. References: (1) B. N. Chakraborty et al. Plant Pathol. 55:303, 2006. (2) E. G. Simmons. Pages 1-35 in: Alternaria Biology, Plant Diseases and Metabolites. J. Chelchowski and A. Visconti, eds. Elsevier, Amsterdam, 1992. (3) A. J. Watson. Plant Dis. Rep. 34:186, 1950.

First Report of Leaf Spot Caused by Phoma exigua on Hydrangea macrophylla in Italy

Hydrangea macrophylla is grown in Italy as a potted plant and also for landscaping. During the fall of 2005 in a nursery located in Lazio (central Italy), a severe foliar disease was observed on 12-month-old potted plants of cv. Hanabi. Small necrotic spots surrounded by chlorotic haloes were observed on the upper side of infected leaves. At temperatures near 20°C and relative humidity ranging between 80 to 90%, spots enlarged to form round areas 2 to 7 cm in diameter that were well defined by a brown margin. Severely infected leaves became chlorotic and abscised. Heavily affected plants were defoliated. Infected plants rarely died, but the presence of lesions on mature plants decreased aesthetic quality and subsequent market value. The disease occurred on 30% of the plants in one nursery. Stems and flowers were not affected by the disease. From infected leaves, a fungus was consistently isolated on potato dextrose agar with 25 mg/liter of streptomycin added. The fungus was grown on leaf extract agar, 30 g of leaves per liter, and maintained at 22°C (12 h of light and 12 h of dark). After 30 days, black pycnidia 275 to 255 μm in diameter developed, releasing conidia that were hyaline, elliptical, nonseptate, and measuring 4.6 to 7.6 (average 6.0) × 1.4 to 4.2 (average 2.6) μm. On oatmeal agar, the addition of a drop of concentrated NaOH caused a positive reaction, turning the medium red (2). On the basis of its morphological characteristics, the fungus was identified as a Phoma sp. The ITS (internal transcribed spacer) region of rDNA was amplified using the primers ITS4/ITS6 (3) and sequenced. BLASTn analysis (1) of the 560 bp obtained showing an E-value of 0.0 with Phoma exigua. The nucleotide sequence has been assigned GenBank Accession No. DQ384612. Pathogenicity tests were performed by spraying leaves of healthy 6-month-old potted H. macrophylla (cvs. Hanabi and Zaffiro) plants with a spore and mycelial suspension (10⁵ CFU/ml). Plants without inoculation served as controls. Five plants were used for each treatment. Plants were covered with plastic bags for 5 days after inoculation and kept in a growth chamber at 20°C with relative humidity at 80 to 90%. The first lesions developed on leaves of cv. Hanabi 12 days after inoculation, while control plants remained healthy. Lesions did not develop on inoculated cv. Zaffiro plants. The fungus was consistently reisolated from the lesions of cv. Hanabi. The pathogenicity test was carried out twice. The presence of P. exigua on H. macrophylla has been reported in the United States (4). In Italy, the disease can be found in a limited area. References: (1) S. F. Altschud et al. Nucleic Acids Res. 25:3389, 1997. (2) G. H. Boerema and L. H. Howeler. Persoonia 5:15, 1967. (3) D. E. L. Cooke and J. M. Duncan. Mycol. Res. 101:667, 1997. (4) M. L. Daughtrey et al. Page 26 in: Compendium of Flowering Potted Plant Diseases. The American Phytopathological Society. St. Paul, MN, 1995.

First Report of Rhizoctonia solani AG 4 on Lamb's Lettuce in Italy

Lamb's lettuce or corn salad (Valerianella olitoria) is increasingly grown in Italy and used primarily in the preparation of mixed processed salad. In the fall of 2005, plants of lamb's lettuce, cv Trophy, exhibiting a basal rot were observed in some commercial greenhouses near Bergamo in northern Italy. The crown of diseased plants showed extensive necrosis, progressing to the basal leaves, with plants eventually dying. The first symptoms, consisting of water-soaked zonate lesions on basal leaves, were observed on 30-day-old plants during the month of October when temperatures ranged between 15 and 22°C. Disease was uniformly distributed in the greenhouses, progressed rapidly in circles, and 50% of the plants were affected. Diseased tissue was disinfested for 1 min in 1% NaOCl and plated on potato dextrose agar amended with 100 μg/liter of streptomycin sulfate. A fungus with the morphological characteristics of Rhizoctonia solani was consistently and readily isolated and maintained in pure culture after single-hyphal tipping (3). The five isolates of R. solani, obtained from affected plants successfully anastomosed with tester isolate AG 4, no. RT 31, received from R. Nicoletti of the Istituto Sperimentale per il Tabacco, Scafati, Italy (2). The hyphal diameter at the point of anastomosis was reduced, and cell death of adjacent cells occurred (1). Pairings were also made with AG 1, 2, 3, 5, 7, and 11 with no anastomoses observed between the five isolates and testers. For pathogenicity tests, the inoculum of R. solani (no. Rh. Vale 1) was grown on autoclaved wheat kernels at 25°C for 10 days. Plants of cv. Trophy were grown in 10-liter containers (20 × 50 cm, 15 plants per container) on a steam disinfested substrate (equal volume of peat and sand). Inoculations were made on 20-day-old plants by placing 2 g of infected wheat kernels at each corner of the container with 3 cm as the distance to the nearest plant. Plants inoculated with clean wheat kernels served as controls. Three replicates (containers) were used. Plants were maintained at 25°C in a growth chamber programmed for 12 h of irradiation at a relative humidity of 80%. The first symptoms, consisting of water-soaked lesions on the basal leaves, developed 5 days after inoculation with crown rot and plant kill in 2 weeks. Control plants remained healthy. R. solani was consistently reisolated from infected plants. The pathogenicity test was carried out twice with similar results. This is, to our knowledge, the first report of R. solani on lamb's lettuce in Italy as well as worldwide. The isolates were deposited at the AGROINNOVA fungal collection. The disease continues to spread in other greenhouses in northern Italy. References: (1) D. Carling. Rhizoctonia Species: Pages 37-47 in: Taxonomy, Molecular Biology, Ecology, Pathology and Disease Control. B. Sneh et al., eds. Kluwer Academic Publishers, the Netherlands, 1996. (2) J. Parmeter et al. Phytopathology, 59:1270, 1969. (3) B. Sneh et al. Identification of Rhizoctonia Species. The American Phytopathological Society, St. Paul, MN, 1996.

First Report of Southern Blight Incited by Sclerotium rolfsii on Potato (Solanum tuberosum) in Northern Italy

During the summer of 2005, plants of potato (Solanum tuberosum L.) showing severe basal rot symptoms were observed in a commercial field near Alessandria (northern Italy). The first symptoms were detected during early July in correspondence with a strong increase of air temperature (as much as 38°C, with an average monthly increase of 10°C) and relative humidity. Infected plants showed dry collar rots and extensive necrosis of cortical tissues. Leaves of infected plants were chlorotic. As the disease progressed, tubers rotted and plants wilted. Infected plants appeared in patches, encompassing 10 to 15% of the cultivated area. In the presence of abundant moisture, a white mycelium occurred on infected tissues. On their surface, infected tubers showed a fan-like mycelial growth. Later, white or light-to-dark brown sclerotia (2 to 4 mm in diameter) developed from mycelium. Clamp connections were present. The diseased tissue was disinfested for 1 min in 1% NaOCl and plated on potato dextrose agar (PDA) amended with 100 mg/liter of streptomycin sulfate. Sclerotium rolfsii was consistently isolated from infected plants. Pathogenicity of one isolate obtained from infected plants was confirmed by inoculating healthy S. tuberosum plants (cv. Hermes) grown in 2:l volume pots (1 plant per pot, seven replicates). Inoculum that consisted of 1 g/pot of wheat kernels infested with mycelium and sclerotia was placed on the soil surface. Seven noninoculated plants served as controls. The inoculation trial was repeated once. Plants were kept at temperatures ranging between 25 and 32°C and watered as needed. Inoculated plants developed symptoms of leaf yellowing within 10 days, soon followed by the appearance of white mycelium and sclerotia and then eventually wilted. Control plants remained symptomless. Sclerotium rolfsii was reisolated from inoculated plants.Possible attacks of Sclerotium rolfsii on S. tuberosum were described as rarely occurring in southern Italy (3). The disease, detected at the moment in very few farms and on cvs. Hermes and Monalisa, was particularly severe on the last variety, causing 5 to 15% yield losses because of premature plant death and rotting of tubers. This disease has been reported in several countries such as India (1), Israel (2), and the United States of America (4). References: (1) N. S. Bisht. Indian Phytopathol. 35:148, 1982. (2) Y. Elad et al. Soil Biol. Biochem. 16:381, 1984. (3) R. Gigante. Ital. Agric. 87:263, 1946. (4) G. F. Weber. Phytopathology, 33:615, 1943.

First Report of Powdery Mildew Caused by Podosphaera leucotricha on Photinia × fraserii in Italy

Photinia × fraserii, belonging to the family Rosaceae, is an evergreen shrub used in parks and gardens. During the spring of 2004, severe outbreaks of a previously unknown powdery mildew were observed in a public park at Torino (northern Italy) on established plantings of this species. The adaxial and abaxial surfaces of leaves were covered with white mycelium and conidia. Stems also had signs of powdery mildew and were chlorotic. As the disease progressed, infected leaves turned yellow and abscised. Conidia formed in chains and were hyaline, ellipsoid, and measured 16.8 to 33.6 × 12.0 to 24.0 μm (average 25.6 × 15.6 μm). On the basis of host, morphological characteristics, and the presence of fibrosin bodies, the pathogen was identified as Podosphaera leucotricha (Ellis & Everth.) E.S. Salmon (2). Pathogenicity was confirmed by inoculating young leaves of 2-year-old Photinia × fraserii plants with a spore suspension (3 × 10⁵ spores per ml). Also, three 3-year-old cv. Golden Delicious potted apple plants were inoculated. Three noninoculated Photinia × fraserii and three noninoculated apple plants sprayed with deionized water served as a control. After inoculation, plants were maintained in a growth chamber at 25°C. After 17 days, powdery mildew symptoms were observed on inoculated plants of Photinia × fraserii and cv. Golden Delicious. Noninoculated plants remained healthy. The pathogenicity test was carried out twice. The pathogenicity on apple supported the identification of the pathogen as P. leucotricha. To our knowledge, this is the first report of powdery mildew on Photinia × fraserii in Italy. P. leucotricha was previously described on Photinia serrulata in Italy (1) and the United States (3). Voucher specimens are available at the AGROINNOVA Collection, University of Torino. References: (1) E. Baldacci. Rev. Appl. Mycol. 16:358, 1937. (2) R. T. A. Cook et al. Mycol. Res. 101:975, 1997. (3) J. A. Milbraith. Rev. Appl. Mycol. 17:751, 1938.