First Report of Sclerotinia Blight Caused by Sclerotinia sclerotiorum on Spearmint in Northern Italy

Spearmint (Mentha spicata L.) is an aromatic plant belonging to the family Lamiaceae, grown as well as an ornamental potted plant. During the beginning of 2013, extensive wilting was observed on 4-month-old potted plants of M. spicata 'Moroccan' grown in a commercial, unheated, plastic house located near Albenga (Savona, northern Italy). Initial symptoms included stem necrosis and darkening and withering of leaves. Wilting of the plant occurred 2 to 4 days after the appearance of the initial symptoms. Infected plants were characterized by the presence of cottony soft rot. In the presence of high relative humidity, lesions became covered with a whitish mycelium and irregular, dark gray sclerotia (2.0 to 9.0 × 1.8 to 4.0, average 4.0 × 2.6 mm) were produced on the mycelium. Diseased tissue was surface sterilized for 1 min in 1% NaOCl and plated on potato dextrose agar (PDA) amended with 100 mg/l streptomycin sulfate. White colonies developed from infected stem pieces and produced sclerotia, mainly at the peripheries of the plates, measuring 2.0 to 8.0 × 2.0 to 6.0 (average 4.4 × 3.1) mm. The internal transcribed spacer (ITS) region of rDNA was amplified using the primers ITS1F/ITS4 and sequenced. BLAST analysis (1) of the 514-bp segment showed a 99% homology with the sequence of Sclerotinia sclerotiorum (JN012605). The nucleotide sequence has been assigned the GenBank Accession KC848769. The morphological and molecular identification permitted to identify as S. sclerotiorum (Lib.) de Bary (2) the causal agent of the disease observed on M. spicata. Pathogenicity of one isolate obtained from infected plants was confirmed by inoculating three 7-month-old plants cv. Moroccan transplanted in 1 liter pots in a glasshouse in a sphagnum peat/pomix/pine bark/clay (50:20:20:10) mix. Each plant was inoculated by placing 4 g of sterile wheat kernels infested with mycelium and sclerotia in the soil and around the collar. Three non-inoculated plants served as controls. Plants were maintained in a growth chamber at 24 ± 1°C and relative humidity >90%. The inoculation trial was carried out twice. All inoculated plants developed the symptoms, consisting of stem necrosis, 5 days after soil infestation, followed by leaf yellowing. White cottony mycelium and dark sclerotia developed on stems and at the base of all inoculated plants. Eventually, infected plants wilted. Control plants remained symptomless. S. sclerotiorum was reisolated from the stems of inoculated plants. To our knowledge, this is the first report of S. sclerotiorum on M. spicata in Italy as well as worldwide. The disease has been previously reported on M. piperita in the United States (4) and on M. arvensis in India (3). The economic importance of this disease in Italy is at present limited. References: (1) S. F. Altschul et al. Nucleic Acids Res. 25:3389, 1997. (2) N. F. Buchwald. Kongl. Veterisk Landb. Aarssk. 75, 1949. (3) K. Perveen et al. Indian Phytopathol. 62:310, 2009. (4) C. B. Skotland and J. D. Menzies. Plant Dis. Rep. 41:493, 1957.

[Bilateral ureterocele in single collection system: a particular case]

INTRODUCTION

Ureterocele is an uncommon congenital urinary tract malformation, which consists in a cystic dilation of the vesical portion of the ureter. We present a rare case of ureterocele, reviewing the most important aspects and characteristics that make it so unusual.

CASE

Seven year old male admitted for hematuria in the context of afebrile urinary tract infection, the ultrasound revealed a right hydroureteronephrosis (HUN) in a single collecting system and a voiding cystourethogram (VCUG) showed a right ureterocele. A cystoscopy demonstrated the presence of a bilateral orthotopicureterocele in a single collecting system. The patient underwent an endoscopic incision in order to drain the hydronephrotic system. After a month, while performing a check up using ultrasound, we could observe an important reduction in the right HUN, however, it also was acknowledged the presence of dilation of the left distal ureter, reason why it was decided to puncture the left ureterocele.

COMMENTS

We present an unusual case: male with a bilateral orthotopicureterocele in a single collecting system and its clinical management. Its particularity is discussed.

Light affects fumonisin production in strains of Fusarium fujikuroi, Fusarium proliferatum, and Fusarium verticillioides isolated from rice

Three Fusarium species associated with bakanae disease of rice (Fusarium fujikuroi, Fusarium proliferatum, and Fusarium verticillioides) were investigated for their ability to produce fumonisins (FB1 and FB2) under different light conditions, and for pathogenicity. Compared to darkness, the conditions that highly stimulated fumonisin production were yellow and green light in F. verticillioides strains; white and blue light, and light/dark alternation in F. fujikuroi and F. proliferatum strains. In general, all light conditions positively influenced fumonisin production with respect to the dark. Expression of the FUM1 gene, which is necessary for the initiation of fumonisin production, was in accordance with the fumonisin biosynthetic profile. High and low fumonisin-producing F. fujikuroi strains showed typical symptoms of bakanae disease, abundant fumonisin-producing F. verticillioides strains exhibited chlorosis and stunting of rice plants, while fumonisin-producing F. proliferatum strains were asymptomatic on rice. We report that F. fujikuroi might be an abundant fumonisin producer with levels comparable to that of F. verticillioides and F. proliferatum, highlighting the need of deeper mycotoxicological analyses on rice isolates of F. fujikuroi. Our results showed for the first time the influence of light on fumonisin production in isolates of F. fujikuroi, F. proliferatum, and F. verticillioides from rice.

First Report of Web Blight on Oregano (Origanum vulgare L.) Caused by Rhizoctonia solani AG-1-IB in Italy

Origanum vulgare L., common name oregano, family Labiatae, is grown for its aromatic and medicinal properties and as ornamental. In the fall of 2012, a blight was observed in a farm located near Albenga (northern Italy) on 6% of 30,000 50-day-old plants, grown in trays in a peat/perlite mix. Semicircular, water soaked lesions appeared on leaves and stems, starting from the basal ones. As the disease progressed, blighted leaves turned brown, withered, clung to the shoots, and matted on the surrounding foliage. Eventually, infected plants died. Leaf and stem fragments taken from the margin of the diseased tissues belonging to 10 plants were disinfected for 10 s in 1% NaOCl, rinsed with sterile water, and plated on potato dextrose agar (PDA). A fungus with the morphological characters of Rhizoctonia solani was consistently recovered. Three isolates of R. solani obtained from affected plants were successfully anastomosed with R. solani isolate AG 1 (ATCC 58946). Three pairings were made for each tester strain. The hyphal diameter at the point of anastomosis was reduced, the anastomosis point was obvious, and death of adjacent cells was observed. Results were consistent with other reports on anastomosis reactions (2). Isolates from oregano were paired with R. solani isolates AG 2, 3, 4, 6, 7, or 11 and examined microscopically. Anastomosis was not observed in any of the pairings. Tests were conducted twice. Mycelium of 10-day-old isolates from oregano appeared reddish brown, coarse, and radiate. Numerous dark brown sclerotia, 0.3 to 1.0 mm diameter (average 0.7) developed within 10 days after transfer of mycelia to PDA in 90 mm diameter petri dishes at 21 to 24°C. The descriptions of mycelium and sclerotia were typical for subgroup IB Type 1 (4). The internal transcribed spacer (ITS) region of rDNA was amplified using the primers ITS1/ITS4 and sequenced. BLASTn analysis (1) of the 538 bp showed a 99% homology with the sequence of R. solani FJ746937, confirming the morphological identification of the species. The nucleotide sequence has been assigned the GenBank Accession KC493638. For pathogenicity tests, one of the isolates assigned to the anastomosis group AG-1-IB was tested by placing 9 mm diameter mycelial disks removed from PDA 10-day-old cultures of the fungus on leaves of 90-day-old oregano plants (n = 35). Thirty-five plants inoculated with non-inoculated PDA disks served as controls. Plants were covered with plastic bags and maintained in a growth chamber at 25 ± 1°C with 12 h light/dark. The first symptoms, similar to those observed in the farm, developed 3 days after inoculation. Nine days after the artificial inoculation, 50% of plants were dead. About 10 colonies of R. solani were reisolated from infected leaves of inoculated plants. Control plants remained healthy. The pathogenicity test was carried out twice with similar results. Symptoms caused by R. solani have been recently observed on O. vulgare in Greece (3). This is, to our knowledge, the first report of blight of O. vulgare caused by R. solani in Italy. 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, pp. 37-47, 1996. (3) C. D. Holevas et al. Benaki Phytopathol. Inst., Kiphissia, Athens, 19:1-96, 2000. (4) R. T. Sherwood. Phytopathology 59:1924, 1969.

First Report of Web Blight on Rosemary (Rosmarinus officinalis) Caused by Rhizoctonia solani AG-1-IA in Italy

Rosmarinus officinalis L., family Labiatae, is an evergreen shrub used in gardens as an aromatic or ground cover plant. In the summer of 2012, a blight was observed in a farm located near Albenga (northern Italy) on 20% of 150,000 70-day-old plants, grown in trays. Water soaked lesions appeared on leaves and stems. As the disease progressed, blighted leaves turned brown, withered, clung to the shoots, and matted on the surrounding foliage. A light mycelium spread on the substrate. Disease progressed from infected plants to healthy ones and, eventually, infected plants died. Leaf and stem fragments taken from the margin of the diseased tissues belonging to 10 plants were disinfected for 10 s in 1% NaOCl, rinsed with sterile water, and plated on potato dextrose agar (PDA). A fungus with the morphological characters of Rhizoctonia solani was consistently and readily recovered. Three isolates of R. solani obtained from affected plants were successfully paired with R. solani tester strains AG 1, 2, 3, 4, 6, 7, or 11 and examined microscopically. Three pairings were made for each recovered isolate. The isolates of R. solani from rosemary anastomosed only with tester strain AG 1 (ATCC 58946). Results were consistent with other reports on anastomosis reactions (2). Tests were repeated once. Mycelium of 10-day-old isolates from rosemary appeared light brown, compact, and radiate. Numerous dark brown sclerotia, 0.7 to 2.0 mm diameter (average 1.3), developed within 10 days at 20 to 26°C. The descriptions of mycelium and sclerotia were typical for subgroup IA Type 2 (4). The internal transcribed spacer (ITS) region of rDNA was amplified using the primers ITS1/ITS4 and sequenced (GenBank Accession No. KC005724). BLASTn analysis (1) of the 657-bp showed a 99% similarity with the sequence of R. solani GU596491. For pathogenicity tests, inoculum of R. solani was prepared by growing the pathogen on wheat kernels autoclaved in 1-liter glass flasks for 8 days. One of the isolates assigned to the anastomosis group AG 1 IA was tested. Fifteen 90-day-old rosemary plants were grown in 15-liter pots in a steam disinfested peat:pomice:pine bark:clay mix (50:20:20:10) infested with 3 g/liter of infested wheat kernels, placed at the base of the stem. Fifteen plants inoculated with non-infested wheat kernels served as control treatments. Plants were covered with plastic bags and arranged in a growth chamber at 20 to 24°C with 12 h light/dark for 15 days. The first symptoms, similar to those observed in the farm, developed 10 days after inoculation. About 10 colonies of R. solani were reisolated from infected leaves and stems of each inoculated plant. Control plants remained healthy. The pathogenicity test was carried out twice with similar results. Symptoms caused by R. solani have been recently observed on R. officinalis in United States (3), India, and Brazil. This is, to our knowledge, the first report of blight of R. officinalis caused by R. solani in Italy. This disease could cause serious economic losses, because rosemary is one of the most cultivated aromatic plants in the Mediterranean region. 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) G. E. Holcomb. Plant Dis. 76:859, 1992. (4) R. T. Sherwood. Phytopathology 59:1924, 1969.

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.

Efficacy of plant essential oils on postharvest control of rots caused by fungi on different stone fruits in vivo

The antifungal activity of plant essential oils was evaluated as postharvest treatment on stone fruit against brown rot and grey mold rot of stone fruit caused by Monilinia laxa and Botrytis cinerea, respectively. The essential oils from basil (Ocimum basilicum), fennel (Foeniculum sativum), lavender (Lavandula officinalis), marjoram (Origanum majorana), oregano (Origanum vulgare), peppermint (Mentha piperita), rosemary (Rosmarinus officinalis), sage (Salvia officinalis), savory (Satureja montana), thyme (Thymus vulgaris), and wild mint (Mentha arvensis) were tested at two different concentrations on apricots (cv. Kyoto and cv. Tonda di Costigliole), nectarines (cv. Big Top and cv. Nectaross) and plums (cv. Italia and cv. TC Sun). The volatile composition of the essential oils tested was determined by gas chromatography-mass spectrometry analysis. The treatments containing essential oils from oregano, savory, and thyme at 1% (vol/vol) controlled both B. cinerea and M. laxa growing on apricots cv. Tonda di Costigliole and plums cv. Italia and cv. TC Sun; however, the same treatments were phytotoxic for the carposphere of nectarines cv. Big Top and cv. Nectaross. Treatments with 10% (vol/vol) essential oils were highly phytotoxic, notwithstanding their efficacy against the pathogens tested. The essential oils containing as major components α-pinene, p-cymene, carvacrol, and thymol showed similar results on stone fruit, so their antimicrobial activity and the phytotoxicity produced could be based on the concentration of their principal compounds and their synergistic activity. The efficacy of the essential oil treatments on control of fungal pathogens in postharvest depended on the fruit cultivar, the composition and concentration of the essential oil applied, and the length of storage.

First Report of Leaf Spot of Saponaria officinalis Caused by Alternaria nobilis in Italy

Saponaria officinalis (Vize) Simmons (common name bouncingbet) is a low maintenance perennial plant belonging to the Caryophyllaceae family, typically grown in parks and gardens. During the summers of 2011 and 2012, extensive necrosis were observed on leaves of plants grown in private gardens, near Biella (northern Italy). The disease affected 90% of 1- to 2-year-old plants. The first symptoms were usually pale brown lesions 1 to 5 mm in diameter and sometimes coalesced. Lesions were circular to irregular with a dark purple halo, with infected leaves eventually turning chlorotic. The conidia observed on infected leaves were olivaceous brown and obclavate, with a beak. Conidia showed 8 to 15 (average 12) transverse and 4 to 14 (average 11) longitudinal septa, with slight constrictions connected with septa, and were 78.3 to 177.7 (average 135.5) × 19.0 to 34.3 (average 26.5) μm. The beak was 20.0 to 62.2 (average 33.7) μm in length, with 0 to 6 (average 3) transverse septa and no longitudinal septa. The fungus was consistently isolated from infected leaves on potato dextrose agar (PDA). The isolate, grown for 14 days at 20 to 24°C with 10 h of darkness and 14 h of light on sterilized host leaves plated on PDA, produced conidiophores single, unbranched, flexuous, septate with conidia in short chains, similar to those observed on the leaves and previously described. On the basis of its morphological characteristics, the pathogen was identified as Alternaria sp. (3). DNA was extracted using Nucleospin Plant Kit (Macherey Nagel) and PCR carried out using ITS 1/ITS 4 primer (4). A 542-bp PCR product was sequenced and a BLASTn search confirmed that the sequence corresponded to A. dianthi (AY154702), recently renamed A. nobilis (2). The nucleotide sequence has been assigned the GenBank Accession No. JX647848. Pathogenicity tests were performed by spraying leaves of healthy 3-month-old plants of S. officinalis with an aqueous 2 × 10⁵ spore/ml suspension. The inoculum was obtained from cultures of the fungus grown on PDA amended with host leaves for 14 days, in light-dark, at 22 ± 1°C. Plants sprayed only with water served as controls. Four pots (1 plant/pot) were used for each treatment. Plants were covered with plastic bags for 4 days after inoculation and maintained in a glasshouse at 21 ± 1 °C. Lesions developed on leaves 9 days after inoculation with the spore suspension, whereas control plants remained healthy. A. nobilis was consistently reisolated from these lesions. The pathogenicity test was carried out twice. The presence of A. dianthi was reported on S. officinalis in Denmark (1) and Turkey. This is, to our knowledge, the first report of A. nobilis on S. officinalis in Italy. The presence and importance of this disease is, at present, limited. References: (1) P. Neergaard. Danish species of Alternaria and Stemphylium. Oxford University Press, 1945. (2) E. G. Simmons. Mycotaxon 82:7, 2002. (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 Crown and Stem Rot of Crested Molded Wax Agave (Echeveria agavoides) caused by Fusarium oxysporum in Italy

During March 2012, 95% of 24-month-old plants of crested molded wax agave (Echeveria agavoides), a succulent plant belonging to the Crassulaceae family, showed symptoms of a basal stem and leaf rot in a commercial farm near Ventimiglia (northern Italy). Affected plants showed extensive chlorosis from the crown level to the stem apex, followed by yellowing and by the appearance of a water-soaked aspect of stem and leaf tissues. As disease progressed, leaves became brown, wilted, and rotted. Wilting was at first unilateral and later affected the entire plant. Brown discoloration was observed in the vascular system of cut stems and leaves. In some cases, leaves were covered by a whitish-orange mycelium. This produced 3-septate, slightly curved macroconidia with a foot-shaped basal cell and a short apical cell, measuring 27.4 to 39.6 × 3.0 to 4.1 (average 34.2 × 3.7) μm and unicellular, ovoid to elliptical microconidia measuring 4.8 to 11.6 × 1.5 to 3.7 (avg. 7.2 × 2.7) μm. A fungus was consistently isolated from discolored vascular leaf tissues on Komada selective medium. Cultures on potato dextrose agar (PDA) and carnation leaf-piece agar (CLA) were incubated at 24 to 29°C. On PDA, a thin growth of whitish mycelium without pigments in the agar was observed. On CLA, sparse macroconidia, 18.9 to 30.7 × 3.0 to 4.2 (avg. 23.9 × 3.6) μm, microconidia, 4.7 to 7.7 × 1.7 to 3.1 (avg. 6.0 × 2.4) μm, and abundant chlamydospores that were single or paired, terminal and intercalary, rough walled, and 6.8 to 9.5 (avg. 7.7) in diameter were produced. Such characteristics are typical of Fusarium oxysporum (2). Amplification of the internal transcribed spacer (ITS) of the rDNA using primers ITS1/ITS4 (3) yielded a 486-bp band (GenBank Accession No. JX441893). Sequencing and BLASTn analysis of this band showed 100% identity and an E-value of 0.0 with the ITS sequence of F. oxysporum (JN232163). To confirm pathogenicity, five 3-month-old healthy plants of E. agavoides were inoculated by dipping unwounded roots in a conidial suspension (1.0 × 10⁷ CFU/ml) of one isolate of F. oxysporum obtained from affected plants, grown for 10 days in potato dextrose broth. Plants were transplanted into pots filled with steam-sterilized substrate (sphagnum peat-perlite-pine bark-clay 50:20:20:10) and maintained in a glasshouse at 28 to 33°C. Five non-inoculated plants served as a control. Chlorosis and yellowing developed on the inoculated plants 15 days after the inoculation. Basal stem rot and vascular discoloration in the crown and stem developed within 30 days on inoculated plants. A whitish-orange mycelium producing macroconidia covered the affected leaves. Non-inoculated plants remained healthy. F. oxysporum was consistently reisolated from symptomatic plants. The pathogenicity test was conducted twice. A Fusarium sp. has been reported as the causal agent of a stem rot on Echeveria sp. in the U.S. (1). To our knowledge, this is the first report of F. oxysporum on E. agavoides in Italy. The disease is currently present in few nurseries, although it could spread, causing significant economic losses due to the increasing cultivation of E. agavoides in Italy. References: (1) D. F. Farr et al. Fungi on Plants and Plant Products in the United States. APS Press, St. Paul, MN, 1989. (2) J. F. Leslie and B. A. Summerell. The Fusarium Laboratory Manual. Blackwell, Ames, IA, 2006. (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.

Compost suppressiveness against Phytophthora capsicion pepper in potting trials

Suppression of soil-borne plant diseases with composts has been widely studied. Composts suppressive to soil-borne pathogens have been detected in various cropping systems. Vegetable plants are generally propagated in pots, allowing the use of suppressive substrates to control zoospore-producing pathogens, like Phytophthora sp. The objective of the present work was to assess compost suppressiveness against Phytophthora capsici on pepper (cv. Corno di Toro). A municipal compost showing a good suppressive activity in previous trials on vegetable crops was used. Compost was mixed at 10, 20, 40, 60, 80 and 100% (v/v) with a commercial peat substrate, used as control. Substrates have been inoculated at 0.25, 0.5 and 1 g/l with wheat and hemp kernels infested with P. capsici and after one week 10 plants were transplanted for each treatment in 4 trays of 10 liters volume capacity and placed in greenhouse at 20 degrees C. Diseased plants were assessed weekly after transplanting and above-ground biomass of plants was assessed at the end of the trials. Compost applied at 80% significantly controlled the disease at high inoculum density (1 g/l), while at lower inoculums density, 0.25 and 0.5 g/l, reduced compost applications, 40% and 60% respectively, were sufficient to significantly control the disease. The application of compost at 20%, in absence of the pathogen, increased the biomass of pepper plants compared to control. The use of compost based substrates can be a suitable strategy for controlling soil-borne diseases on pepper, but results depends on application rates.

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.

First Report of Verticillium Wilt caused by Verticillium dahliae Kleb. on New Zealand Spinach (Tetragonia tetragonioides) in Italy

Tetragonia tetragonioides (New Zealand spinach, Aizoaceae) is an Australasian annual species that occurs naturally in Italy, where it is cultivated for the edible young shoots and succulent leaves. In September 2011, a previously unknown wilt was observed in 10 private gardens, each 0.1 to 0.5 ha, near Castellaro, Northern Italy, on 7-month-old New Zealand spinach plants. Leaves wilted, starting from the collar and moving up the plant, and vascular tissues showed brown streaks in the roots, crowns, and stems. Diseased plants were stunted with small, chlorotic leaves. Infected stems and leaves then wilted, and plants often died. Of about 500 plants, 30% were affected. Stems of 10 diseased plants were disinfected with 1% NaOCl for 1 min. Sections of symptomatic vascular tissue were plated on potato dextrose agar. After 3 days at 23 ± 1°C, colonies developed that were white and turned a grey to dark green color. Irregular, black microsclerotia (32.0) 63.1 ± 16.8 μm (106.1) × (18.7) 39.1 ± 12.3 μm (65.8) developed in hyaline hyphae after 8 days. Hyaline, elliptical, single-celled conidia (2.7) 3.8 ± 0.6 μm (4.8) × (1.9) 2.6 ± 0.5 μm (3.5) developed on verticillate conidiophores with three phialides at each node. Based on these morphological characteristics, the fungus was identified as Verticillium dahliae (1). The internal transcribed spacer (ITS) region of rDNA was amplified for one isolate using the primers ITS1/ITS4 (3) and sequenced (GenBank Accession No. JX308315). BLASTn analysis of the 479-bp segment showed 100% homology with the ITS sequence of a V. dahliae isolate (AB551206). Pathogenicity tests were performed twice using 60-day-old plants of T. tetragonioides. Unwounded roots of eight plants were dipped for 1 min in a conidial suspension (5 × 10⁷ conidia/ml) of one isolate of V. dahliae obtained from the original infected New Zealand spinach plants, and grown in potato dextrose broth. The inoculated plants were transplanted into 2-liter pots (1 plant/pot) containing steamed potting mix (sphagnum peat-perlite-pine bark-clay; 50:20:20:10) and maintained in a growth chamber at 20 to 24°C and 50 to 80% RH. Eight plants immersed in sterile water served as a control treatment. Wilt symptoms were observed 30 days after inoculation, with vascular discoloration in the roots, crowns and stems. V. dahliae was reisolated consistently from infected tissues, but not from the control plants that remained healthy. Pathogenicity was also tested using the same method on plants of four cultivars (five plants/cultivar) of Spinacia oleracea (Matador, Asti, Merlo Nero, and America). Wilt symptoms developed on all cultivars and V. dahliae was reisolated from each inoculated plant. No fungal colonies were reisolated from control plants, which remained healthy. To our knowledge, this is the first report of Verticillium wilt caused by V. dahliae on T. tetragonioides in Italy, as well in Europe. V. dahliae was reported on T. tetragonioides in Canada (2). At this time, the economic impact of Verticillium wilt on New Zealand Spinach in Italy is limited, although the use of this vegetable in Italy is increasing. References: (1) G. F. Pegg and B. L. Brady. Verticillium Wilts. CABI Publishing, Wallingford, UK, 2002. (2) M. J. Richardson. Page 387 in: An Annotated List of Seed-Borne Diseases, Fourth Edition. International Seed Testing Association, Zurich, Switzerland, 1990. (3) T. J. White et al. Page 315 in: PCR Protocols. A Guide to Methods and Applications. Academic Press, San Diego, CA, 1990.

Detection of Fusarium oxysporum f.sp. basilici in substrates and roots by PCR

Fusarium oxysporum is a soil-borne fungus that causes vascular wilts in a wide variety of plant species. Basil is recognized as an ecological niche for Fusarium oxysporum f.sp. basilici (FOB) and this fungus is now present in most countries where basil is cultivated. The rapid identification of the species affecting basil plants is necessary to define a successful method for crop protection. The aim of this study was to develop a PCR method for the rapid detection of Fusarium oxysporum f. sp. basilici in substrates. The specificity of the primers used was tested using the DNA extracted directly from substrate samples. Fusarium oxysporum f.sp. basilici was artificially inoculated with decreasing amounts in a commercial substrate (sphagnum peat moss) and in a mixture with 40% of municipal compost, after steam disinfestation. Basil seeds (cv. Fine verde) were sown in pots that were laid on a bench in the greenhouse. At time 0 and after 7, 14 and 21 days from the inoculation, substrate and root samples were collected and prepared for microbial analysis and for the DNA extraction. DNA extraction was carried out using NucleoSpin Soil Kit (Macherey-Nagel, Germany). PCR amplification for the specific detection was carried out using primer sets Bik 1 (5'-ATT CAA GAG CTA AAG GTC C-3') and Bik 4 (5'-TTT GAC CAA GAT AGA TGC C-3') for the first PCR, while primers Bik 1 + Bik 2 (5'-AAA GGT AGT ATA TCG GAG G-3') for the nested PCR to increase detection sensitivity. Disease incidence was also assessed 21 days after seeding. The results showed the presence of amplified fragments of the expected size when the concentration of F. oxysporum f.sp. basilici was at least 3.5 Log CFU g(-1) by using DNA extract directly from substrate, before roots were infected by the pathogen. The detection of Fusarium oxysporum f. sp. basilici by PCR method developed in this study is certainly simple and fast and can be useful for its reliable detection in substrate samples, but not to guarantee that the substrate is totally free of pathogens.

Podosphaera sp. on Euphorbia susannae and E. inermis in Italy

Euphorbia susannae (common name Suzane's spurge) and E. inermis (Euphorbiaceae family) are grown in pots and commercialized in northern Italy. In March 2012, plants of these species grown on the same commercial farm showed signs of powdery mildew. On E. susannae, apexes of stems were covered with white mycelia and conidia, with the ultimate development of necrosis on symptomatic tissues more interested by the disease. Of 5,000 plants, 5% were affected. Conidia were hyaline, elliptical, borne in short chains (two to three conidia per chain), and 27.7 (24.4 to 30.6) μm long and 16.1 (13.6 to 19.1) μm wide. Conidiophores were erect, with a foot cell straight or slightly flexuous, 82.8 (52.7 to 117.1) μm long and 10.0 (9.2 to 11.2) μm wide, followed by two to three shorter cells 19.8 (14.7 to 28.9) μm long and 10.7 (8.7 to 13.0) μm wide. On E. inermis, a white mycelium covered the stems starting from the apexes, causing yellowing and necrosis on leaves finally killing infected tissues. Of 500 plants, 80% were affected. Conidia were 33.2 (25.7 to 42.0) μm long and 17.3 (12.6 to 21.6) μm wide. Conidiophores were erect, with a foot cell straight or slightly flexuous, 96.7 (67.0 to 138.6) μm long and 9.5 (7.7 to 11.7) μm wide, followed by two to three shorter cells 26.3 (17.5 to 42.2) μm long and 11.8 (8.3 to 16.2) μm wide. Fibrosin bodies were present on both hosts, while chasmothecia were not observed in samples from either host. The internal transcribed spacer (ITS) region of rDNA of samples of mycelium and conidia collected from the two hosts was amplified using the primers ITS1-ITS4 (3) and directly sequenced (GenBank Accession Nos. JX179221 and JX179219 for E. susannae and E. inermis, respectively). By performing BLAST analysis, the 692-bp amplicon from E. susannae and the 541-bp amplicon from E. inermis showed 100% homology with several sequences of Podosphaera spp. On the basis of morphological characteristics of the imperfect state and the ITS analysis, the causal agent of powdery mildew on E. susannae and E. inermis was identified as Podosphaera sp. Pathogenicity was confirmed by gently brushing healthy 20-month-old potted plants of E. susannae and E. inermis with mycelia and conidia from diseased plants. Four plants/treatment/species were used. Non-inoculated plants belonging to the two species served as control. Plants were maintained in a glasshouse at temperatures ranging from 18 to 25°C and relative humidity from 65 to 80%. About 20 days after inoculation, typical symptoms of powdery mildew developed on inoculated plants. The fungus observed on inoculated plants was morphologically identical to the original isolate. Non-inoculated plants did not exhibit symptoms. The pathogenicity test was performed in duplicate. Several agents of powdery mildew have been reported on Euphorbia spp. Among others, Podosphaera euphorbiae was reported on numerous Euphorbiaceae (1), P. euphorbiae-hirtae was observed on E. hirta (1) and P. euphorbiae-helioscopiae on E. pekinensis (2). To our knowledge, this is the first report of Podosphaera sp. on E. susannae and E. inermis in Italy. This disease is not presently of economic importance. Specimens are available at the Agroinnova Collection. References: (1) U. Braun. A Monograph of the Erysiphales (Powdery Mildews). J. Cramer, Berlin-Stuttgard, German Democratic Republic, 1987. (2) S. Y. Liu. Plant Dis. 95:1314, 2011. (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.

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 Fusarium oxysporum Causing Wilt on Iceland Poppy (Papaver nudicaule) in Italy

During fall 2011, symptoms of a wilt disease were observed in a commercial nursery near Ventimiglia as well as in the Research Center of Floriculture of Sanremo (northern Italy) on plants of Papaver nudicaule (Iceland poppy) of a local unnamed cultivar. In the commercial nursery, 15 to 20% of plants were affected, while about 3% of plants were affected at the Research Center. Symptoms consisted of chlorosis, premature leaf drop, and foliar wilting, followed by the stem wilting, bending, and eventually rotting from the base. Brown discoloration was observed in the stem vascular tissue. Using Komada's Fusarium-selective agar medium (2), a fungus was consistently and readily isolated from symptomatic vascular tissue of plants collected from both sites. The isolates were purified and subcultured on potato dextrose agar (PDA), on which medium both isolates produced pale violet, abundant, aerial mycelium, felted in old cultures, with pale purple pigments in the agar medium. The isolate generated short monophialides with unicellular, ovoid-elliptical microconidia of 3.9 to 6.7 × 1.4 to 3.0 (average 5.4 × 2.3) μm. On carnation leaf agar (CLA) (1), isolates produced pale orange sporodochia with macroconidia that were 3-septate, slightly falcate with a foot-shaped basal cell and a short apical cell, and 26.0 to 43.5 × 3.1 to 4.4 (average 35.3 × 3.7) μm. Chlamydospores were abundant, terminal, and intercalary, rough walled, mostly singles but sometime in short chains or clusters, and 5.2 to 10.1 μm in diameter. Such characteristics are typical of Fusarium oxysporum (3). The internal transcribed spacer (ITS) region of rDNA was amplified from the isolates using the primers ITS1/ITS4 (4), and sequenced. BLASTn analysis of the 507-bp ITS sequence of one isolate from P. nudicaule collected from the commercial nursery (GenBank Accession No. JX103564) showed an E-value of 0.0 and 100% identity with the ITS sequence of F. oxysporum (HQ649820). To confirm pathogenicity of one of the Iceland poppy isolates, tests were conducted on 2-month-old plants of the same cultivar on which symptoms were first observed. Plants (n = 14) were inoculated by dipping roots in a 1 × 10⁷ CFU/ml conidial suspension of the isolate of F. oxysporum prepared from 10-day-old cultures grown in potato dextrose broth (PDB) on a shaker (90 rpm) for 10 days at 22 ± 1°C (12-h fluorescent light, 12-h dark). Non-inoculated control plants (n = 14) were dipped in sterilized water. All the plants were transplanted into pots filled with steamed potting mix (sphagnum peat/perlite/pine bark/clay at 50:20:20:10), and maintained in a glasshouse at 24 to 28°C. Inoculated plants showed typical symptoms of Fusarium wilt after 10 days. The stems then wilted and plants died. Non-inoculated plants remained healthy. F. oxysporum was reisolated from inoculated plants but not from control plants. The pathogenicity test was conducted twice with the same results. Since Fusarium wilt has not previously been described on Iceland poppy at any location, this is first report of F. oxysporum on P. nudicaule in Italy and anywhere in the world. References: (1) N. L. Fisher et al. Phytopathology 72:151, 1982. (2) H. Komada. Rev. Plant Prot. Res. 8:114, 1975. (3) J. F. Leslie and B.A. Summerell. The Fusarium Laboratory Manual, Blackwell Professional, IA, 2006. (4) T. J. White et al. PCR Protocols: A Guide to Methods and Applications. M. A. Innis et al., eds. Academic Press, San Diego, CA, 1990.

First Report of Root Rot Caused by Phytophthora cinnamomi on Mountain Laurel (Kalmia latifolia) in Italy

Kalmia latifolia L., common name Mountain Laurel, is an evergreen shrub that is becoming increasingly popular in gardens. It is also grown as a potted plant for its round flowers that range from light pink to white and occur in clusters in late spring. During July 2011, 3-year-old plants of K. latifolia 'Olympic Fire' showed extensive chlorosis and root rot on several commercial nurseries close to Maggiore Lake (Verbano-Cusio-Ossola Province) in northwestern Italy. Twigs wilted and died and leaves dropped, although in some cases, wilted leaves persisted on stems. The whole root system was affected with vascular tissues on the lower stem exhibiting brown discoloration, followed by plant death. The disease was severe and widespread, affecting 5% of approximately 3,500 plants. Tissue fragments of 1 mm² were excised from the margins of the lesions and plated. A Phytophthora-like organism was consistently isolated on an oomycete-selective medium (BNPRA + HMI at 25 μg/ml) (4) after disinfesting root pieces for 1 min in a 1% NaOCl solution. The pathogen was identified based on morphological and physiological features as Phytophthora cinnamomi (2). Oogonia didn't form in single culture. On V8 agar, the microorganism was characterized by coenocytic coralloid hyphae, with spherical lateral and terminal swellings 23 to 46 (average 34) μm in diameter (n = 50), single or in clusters, and produced spherical, terminal chlamydospores 35 to 47 (average 40) μm in diameter (n = 50). No sporangia were produced after growing pure cultures in sterilized soil extracts nor were they produced on V8 agar. The internal transcribed spacer (ITS) region of the rDNA of a single isolate was amplified using the primers ITS1/ITS4 and sequenced. BLAST analysis (1) of the 898-bp segment showed a 99% homology with the sequence of P. cinnamomi (GU799638). The nucleotide sequence has been assigned the GenBank Accession No. JQ951607. Pathogenicity of one isolate obtained from infected plants was confirmed by inoculating 18-month-old plants of K. latifolia 'Olympic Fire'. The isolate was grown for 50 days in a mixture of 70:30 wheat/hemp kernels and then mixed into a substrate containing sphagnum peat moss/pumice/pine bark/clay (50:20:20:10 v/v) at a rate of 3 g/l. One plant per 2-l pot was transplanted into the substrate and constituted the experimental unit. Five plants were inoculated. Noninoculated plants represented the control treatment and the trial was repeated once. All plants were kept in a greenhouse at 24 to 27°C. Two of five plants inoculated developed symptoms of chlorosis, wilting, and root rot after 70 days and remaining plants after about 80 days. P. cinnamomi was reisolated consistently from inoculated plants but not from controls that remained symptomless. To our knowledge, this is the first report of P. cinnamomi on K. latifolia in Italy and in Europe. The disease has been reported in the United States (3). The economic importance of the disease is uncertain because of the limited number of nurseries that grow this crop in Italy, although its importance could increase as the popularity of K. latifolia increases. References: (1) S. F. Altschul et al. Nucleic Acids Res. 25:3389, 1997 (2) D. C. Erwin and O. K. Ribeiro. Phytophthora Diseases Worldwide. American Phytopathological Society, St Paul, MN, 1996. (3) L. F. Grand. North Carolina Agric. Res. Serv. Techn. Bull. 240, 1985. (4) H. Masago et al. Phytopathology 67:425, 1977.

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 Fruit Rot in Pear Caused by Botryosphaeria dothidea in Italy

Pear (Pyrus communis L.) is widely grown in Italy, the leading producer in Europe. In summer 2011, a previously unknown rot was observed on fruit of an old cultivar, Spadoncina, in a garden in Torino Province (northern Italy). The decayed area of the fruit was soft, dark brown, slightly sunken, circular, and surrounded by an irregular margin. The internal decayed area appeared rotten and brown and rotted fruit eventually fell. To isolate the causal agent, fruits were soaked in 1% NaOCl for 30 s and fragments (approximately 2 mm) were taken from the margin of the internal diseased tissues, cultured on potato dextrose agar (PDA), and incubated at temperatures between 20 and 28°C under alternating light and darkness. Colonies of the fungus initially appeared whitish, then turned dark gray. After about 30 days of growth, unicellular elliptical hyaline conidia were produced in pycnidia. Conidia measured 16 to 24 × 5 to 7 (average 20.1 × 5.7) μm (n = 50). The morphological characteristics are similar to those of the fungus Botryosphaeria dothidea (Moug.: Fr.) Ces. & De Not. (4). The internal transcribed spacer (ITS) region of rDNA was amplified with the primers ITS1/ITS4 and sequenced. BLAST analysis (1) of the 473-bp segment showed a 100% similarity with the sequence of the epitype of B. dothidea AY236949. The nucleotide sequence has been assigned the GenBank Accession No. JQ418493. Pathogenicity tests were performed by inoculating six pear fruits of the same cultivar (Spadoncina) after surface disinfesting in 1% sodium hypochlorite and wounding. Mycelial disks (8 mm diameter), obtained from 10-day-old PDA cultures of one strain, were placed on wounds. Six control fruits were inoculated with plain PDA. Fruits were incubated at 25 ± 1°C in plastic boxes. The first symptoms developed 3 days after inoculation. After 5 days, the rot was very evident and B. dothidea was consistently reisolated. Noninoculated fruits remained healthy. The pathogenicity test was performed twice. B. dothidea was identified on decayed pears in the United States (2), South Africa, New Zealand, Japan, and Taiwan (3). To our knowledge, this is the first report of the presence of B. dothidea on pear in Italy, as well as in Europe. In Italy, the economic importance of the disease on pear fruit is at present limited, although the pathogen could represent a risk for this crop. References: (1) S. F. Altschul et al. Nucleic Acids Res., 25:3389, 1997. (2) L. F. Grand. Agr. Res. Serv. Techn. Bull. 240:1, 1985. (3) Y. Ko et al. Plant Prot. Bull. (Taiwan) 35:211, 1993. (4) B. Slippers et al. Mycologia 96:83, 2004.

First Report of Leaf Spot of Garden Lupin (Lupinus polyphyllus) Caused by Pleiochaeta setosa in Italy

Lupinus polyphyllus Lindl., common name garden lupin, is used in commercial, private, and public landscapes and sold as a cut flower. During summer 2011, extensive brown necrotic areas were observed on young and old leaves of plants grown in a private garden near Biella (northern Italy). The disease affected about 50 of 80 2-year-old plants. Early symptoms included circular to irregular-shaped brown lesions of alternating pale and dark brown concentric bands. Lesions coalesced and often were surrounded by chlorotic halos at an advanced development stage. Lesion expansion was not limited by leaf veins. When lesions covered much of the leaf area, the leaf curled and remained attached. However, expansion of stem lesions often resulted in plant death. A fungus was consistently isolated from 15 infected leaves on potato dextrose agar (PDA). Cultures were grown at 21 to 25°C under 16 h of light and 8 h of darkness. Mature colonies were dark olive-green and produced orangeochre pigments in the medium. Ten isolates were obtained and three strains were used in the morphological study. The mycelium had olivaceous, septate hyphae that produced abundant dark, intercalary chlamydospores. The conidia were cylindrical to elliptical, slightly curved, with a truncated base, five to seven transverse septa and three hyaline appendages. Apical and basal cells were subhyaline, whereas the intermediate cells were olivebrown. The conidia measured 76 to 94 × 14 to 19 (average 85 × 16) μm. Appendages were up to 84 μm long. On the basis of its morphological characteristics the pathogen was identified as Pleiochaeta setosa Kirchn. DNA was extracted using Terra PCR Direct Polymerase Mix (Clontech). The internal transcribed spacer region of rDNA was amplified using primers ITS 1 and 4 (4) and sequenced. BLAST analysis (1) of the 570 bp fragment showed a 100% homology with a P. setosa isolate submitted to GenBank (accession no. EU167563). The nucleotide sequence was submitted to GenBank (JQ358708). Pathogenicity was verified on healthy 5-month-old garden lupin plants by placing 8-mm mycelial disks from 15-day-old cultures on 10 unwounded leaves per plant with five plants per treatment. Ten leaves of five plants were inoculated with PDA disks to serve as a negative control. Plants were covered with plastic bags for 4 days after inoculation and maintained in a growth chamber at 20 ± 1°C. Lesions developed on 80% of leaves 3 days after inoculation, whereas control plants remained healthy. P. setosa was consistently isolated from these lesions. The pathogenicity test was carried out twice. The presence of P. setosa on L. polyphyllus was reported in Australia, United States (2), and Poland (3). This is, to our knowledge, the first report of P. setosa in Italy. The impact of this disease is currently limited. References: (1) S. F. Altschul et al. Nucleic Acids Res., 25:3389, 1997. (2) A. M. French. California Plant Disease Host Index. Calif. Dept. Food Agric. Sacramento, 1989. (3) W. Mulenko et al. A Preliminary Checklist of Mycromycetes in Poland Polish Academy of Sciences, 1982. (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.

A bacterial-fungal metaproteomic analysis enlightens an intriguing multicomponent interaction in the rhizosphere of Lactuca sativa

Fusarium oxysporum MSA 35 [wild-type (WT) strain] is an antagonistic isolate that protects plants against pathogenic Fusaria. This strain lives in association with ectosymbiotic bacteria. When cured of the prokaryotic symbionts [cured (CU) form], the fungus is pathogenic, causing wilt symptoms similar to those of F. oxysporum f.sp. lactucae. The aim of this study was to understand if and how the host plant Lactuca sativa contributes to the expression of the antagonistic/pathogenic behaviors of MSA 35 strains. A time-course comparative analysis of the proteomic profiles of WT and CU strains was performed. Fungal proteins expressed during the early stages of plant-fungus interaction were involved in stress defense, energy metabolism, and virulence and were equally induced in both strains. In the late phase of the interkingdom interaction, only CU strain continued the production of virulence- and energy-related proteins. The expression analysis of lettuce genes coding for proteins involved in resistance-related processes corroborated proteomic data by showing that, at the beginning of the interaction, both fungi are perceived by the plant as pathogen. On the contrary, after 8 days, only the CU strain is able to induce plant gene expression. For the first time, it was demonstrated that an antagonistic F. oxysporum behaves initially as pathogen, showing an interesting similarity with other beneficial organisms such as mychorrizae.

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.