Phylogeny, Morphology, Distribution, and Pathogenicity of Botryosphaeriaceae and Diaporthaceae from English Walnut in California

Identification and Pathogenicity of Fungal Species Associated with Branch Canker and Shoot Blight on Persimmons (Diospyros kaki) in California

Persimmon is a relatively new crop to California agriculture. Asian persimmons (Diospyros kaki) are the dominant species commercially cultivated in the United States, primarily grown in California, covering approximately 1,153 ha of bearing trees. In the growing seasons of 2020 and 2021, unusual shoot blight and branch cankers were observed in several persimmon orchards in San Joaquin and Solano counties in California. The most prevalent symptoms were well-defined black discoloration in the cambium and streaking in the vascular tissues of green shoots. On woody branches and old pruning wounds, symptoms manifested as black wedge-shaped cankers. Isolations from affected tissues revealed the occurrence of Diaporthe species, including D. chamaeropis, D. foeniculina, and an undescribed Diaporthe sp. as the most frequent isolated pathogens, followed by Eutypella citricola and Phaeoacremonium iranianum. The isolates were identified through multilocus phylogenetic analyses using nucleotide sequences of the rDNA internal transcribed spacer, β-tubulin, and translation elongation factor 1-alpha genes. To fulfill Koch's postulates, mycelium plugs of the various fungal species identified were inserted in 2-year-old branches of mature persimmon trees after making wounds using a corkborer in field conditions. Results showed that Diaporthe spp., E. citricola, and P. iranianum are the main causal agents of branch canker and shoot dieback of persimmon trees in California, with Diaporthe spp. being the most frequently isolated pathogen.

Emergence of Lasiodiplodia theobromae induced leaf necrosis in tea (Camellia sinensis [L.] O. Kuntze) from India

The tea plant, Camellia sinensis [L.] O. Kuntze, is a vital global agricultural commodity, yet faces challenges from fungal infections, which affects its production. To reduce the loss in the tea production, the fungal infections must be removed which is managed with fungicides, which are harmful to the environment. Leaf necrosis, which decreases tea quality and quantity, was investigated across Assam, revealing Lasiodiplodia theobromae as the causative agent. Pathogenicity tests, alongside morphological and molecular analyses, confirmed its role in leaf necrosis. Genome and gene analysis of L. theobromae showed multiple genes related to its pathogenicity. The study also assessed the impact of chemical pesticides on this pathogen. Additionally, the findings in this study highlight the significance of re-assessing management approaches in considering the fungal infection in tea.

Heart Rot Disease of Walnut Caused by Nothophoma juglandis sp. nov. and Its Endophytic Biocontrol Agent

English walnut (Juglans regia L.) is an economically important hardwood tree species cultivated worldwide. Walnut heart rot disease leading to heartwood decay of trees has been frequently observed in a number of plantations in China. To identify the causal agent, 29 diseased stem samples were collected from walnut plantations in Beijing, and 54 fungal isolates were obtained. Koch's postulates were developed, and the results showed that Nothophoma juglandis, a species new to science, was the causal agent of walnut heart rot disease. Granulobasidium vellereum, a notable biocontrol agent, was coisolated with N. juglandis. An antagonistic assay on dual culture and walnut stems (both in the field and detached branches) proved that G. vellereum acted as a potential biocontrol agent against N. juglandis, as it could significantly inhibit the expansion of N. juglandis. The optimal temperature for mycelial growth and pathogenicity of N. juglandis was 26.6 and 27.0°C, respectively, which frequently occur in the summer of the walnut-growing regions in China.

Isolation and Reproductive Structures Induction of Fungal Pathogens Associated with Xylem and Wood Necrosis in Grapevine

Grapevine (Vitis vinifera L.) trunk diseases (GTDs) are considered a disease complex including five diseases: esca, Petri disease, black-foot disease, Botryosphaeria dieback, and Eutypa dieback. The main symptom is a general decline in affected plants, which show xylem necrosis and discoloration or sectorial necrosis in the wood. Their diagnosis is tedious due to four main reasons: (i) the wide diversity of internal symptoms that we can find; (ii) the great diversity of fungi that are associated with them; (iii) the high frequency of co-infections in the same plant; and (iv) the different behavior that the fungal species associated with GTDs show in vitro. Here, we describe a detailed protocol to isolate the different fungal trunk pathogens associated with GTDs as well as methods to induce sporulation and formation of fruiting bodies (pycnidia) to make easier their morphological characterization.

Plant-Associated Neoscytalidium dimidiatum-Taxonomy, Host Range, Epidemiology, Virulence, and Management Strategies: A Comprehensive Review

Neoscytalidium dimidiatum, a plant- and human-associated fungus, has emerged as a substantial global ecological and agricultural threat aggravated by global warming. It inflicts various diseases, including canker, blight, dieback, leaf spot, root rot, and fruit rot, across a wide spectrum of fruit trees, field crops, shrubs, and arboreal species, with a host range spanning 46 plant families, 84 genera, and 126 species, primarily affecting eudicot angiosperms. Six genera are asymptomatic hosts. Neoscytalidium dimidiatum exhibits worldwide distribution, with the highest prevalence observed in Asia and North America, notably in Iran, Turkey, and California. Rising disease prevalence and severity, aggravated by climate change, particularly impact tropical arid places across 37 countries spanning all 7 continents. This comprehensive review encapsulates recent advancements in the understanding of N. dimidiatum, encompassing alterations in its taxonomic classification, host range, symptoms, geographic distribution, epidemiology, virulence, and strategies for effective management. This study also concentrates on comprehending the taxonomic relationships and intraspecific variations within N. dimidiatum, with a particular emphasis on N. oculus and N. hylocereum, proposing to consider these two species as synonymous with N. dimidiatum. Furthermore, this review identifies prospective research directions aimed at augmenting our fundamental understanding of host-N. dimidiatum interaction.

Molecular Identification and Characterization of Fusarium Associated with Walnut Branch Blight Disease in China

In October 2020, samples of walnut branch blight were collected from Longnan. Pathogens were isolated and identified based on morphological and molecular features, and their characteristics were analyzed by pathogenicity. Pathogenicity testing revealed that seven strains (LN-1, LN-3, LN-6, LN-19, LN-27, QY3-1, and QY9-1) induced symptoms of walnut branch blight that were consistent with those observed in the field after inoculation. Furthermore, some Fusarium-type conidia and spherical chlamydospores were visible indicating that they were Fusarium spp. A molecular characterization including sequence and phylogenetic analysis of the ITS, TEF-1α, βTUB, Fu, and LSU gene regions revealed that LN-1 and LN-19 belonged to F. avenaceum, LN-3 and LN-6 to F. acuminatum, LN-27 to F. sporotrichioides, and QY3-1 and QY9-1 to F. tricinctum. This is the first time that F. acuminatum-, F. sporotrichioides-, and F. tricinctum-caused walnut branch blight has been reported in China.

Lasiodiplodia regiae sp. nov.: A New Species Causing Canker and Dieback of Fruit Trees in China

Canker and dieback are serious fungal diseases of woody plants that can cause huge economic losses to orchards. The purpose of this study was to classify and assess the pathogenicity of fungal species associated with canker and dieback on fruit trees growing in Henan Province, China. In total, 150 isolates of Botryosphaeriaceae were obtained from six different fruit trees exhibiting typical symptoms of stem canker, branch dieback, and gummosis. Morphological examinations and phylogenetic analysis of ITS, tef1, tub2, and rpb2 revealed two Botryosphaeriaceae species, which are Botryosphaeria dothidea and a novel species, Lasiodiplodia regiae, respectively. Using Koch's postulates, we confirmed that the different isolates of L. regiae can cause disease in their original hosts. The pathogenicity tests showed that L. regiae can cause canker, dieback, and gummosis symptoms in four different hosts, indicating a relatively wider host range. Moreover, 10 L. regiae isolates exhibited similar symptoms but different levels of virulence on shoots of peach trees under field conditions. This study demonstrated that L. regiae was a new causal agent of canker and dieback of six fruit tree species, which could be a serious risk to the orchard industry in China. Furthermore, the findings provide a foundation for further epidemiological studies and the development of management strategies.

Profiling Walnut Fungal Pathobiome Associated with Walnut Dieback Using Community-Targeted DNA Metabarcoding

Walnut dieback can be caused by several fungal pathogenic species, which are associated with symptoms ranging from branch dieback to fruit necrosis and blight, challenging the one pathogen-one disease concept. Therefore, an accurate and extensive description of the walnut fungal pathobiome is crucial. To this end, DNA metabarcoding represents a powerful approach provided that bioinformatic pipelines are evaluated to avoid misinterpretation. In this context, this study aimed to determine (i) the performance of five primer pairs targeting the ITS region in amplifying genera of interest and estimating their relative abundance based on mock communities and (ii) the degree of taxonomic resolution using phylogenetic trees. Furthermore, our pipelines were also applied to DNA sequences from symptomatic walnut husks and twigs. Overall, our results showed that the ITS2 region was a better barcode than ITS1 and ITS, resulting in significantly higher sensitivity and/or similarity of composition values. The ITS3/ITS4_KYO1 primer set allowed to cover a wider range of fungal diversity, compared to the other primer sets also targeting the ITS2 region, namely, GTAA and GTAAm. Adding an extraction step to the ITS2 sequence influenced both positively and negatively the taxonomic resolution at the genus and species level, depending on the primer pair considered. Taken together, these results suggested that Kyo set without ITS2 extraction was the best pipeline to assess the broadest fungal diversity, with a more accurate taxonomic assignment, in walnut organs with dieback symptoms.

Duplex Real-Time PCR Assays for the Simultaneous Detection and Quantification of Botryosphaeriaceae Species Causing Canker Diseases in Woody Crops

Woody canker diseases caused by fungi of the Botryosphaeriaceae family are producing increasing losses in many economically important woody crops, including almond. To develop a molecular tool for the detection and quantification of the most aggressive and threatening species is of main importance. This will help to prevent the introduction of these pathogens in new orchards and to conveniently apply the appropriate control measures. Three reliable, sensitive and specific duplex qPCR assays using TaqMan probes have been designed for the detection and quantification of (a) Neofusicoccum parvum and the Neofusicoccum genus, (b) N. parvum and the Botryosphaeriaceae family and (c) Botryosphaeria dothidea and the Botryosphaeriaceae family. The multiplex qPCR protocols have been validated on artificially and naturally infected plants. Direct systems to process plant materials, without DNA purification, allowed high-throughput detection of Botryosphaeriaceae targets even in asymptomatic tissues. These results validate the qPCR using the direct sample preparation method as a valuable tool for Botryosphaeria dieback diagnosis allowing a large-scale analysis and the preventive detection of latent infection.

Prevalence, Identity, Pathogenicity, and Infection Dynamics of Botryosphaeriaceae Causing Avocado Branch Canker in California

Botryosphaeria branch canker and dieback of avocado (Persea americana Mill.) has expanded in avocado-growing areas in recent years. Twenty-one avocado groves in the major producing regions of California were surveyed in 2018 and 2019. Monthly inoculations of wounded, green, and lignified branches of 'Hass' and 'Lamb Hass' were conducted. Botryosphaeriaceae were the predominant fungi recovered from cankered tissues collected across the surveyed traditional and high-density orchards and caused symptoms on all six sampled cultivars. These fungi were also recovered in asymptomatic twigs and other organs and thus exist as a potential reservoir for future infections. Molecular analyses of 173 isolates showed that Neofusicoccum luteum had the greatest incidences across sites and cultivars, with 83 and 29% recovered from Hass and Lamb Hass, respectively. Pathogenicity tests on excised (Hass, GEM, and Hass mutants) and attached shoots from potted (Hass) and mature avocado trees (Hass and Lamb Hass) showed that all species were pathogenic on wounded, green, and mature branches of the specified cultivars. Monthly inoculations of wounded, green, and lignified branches of Hass and Lamb Hass showed that both stem types were susceptible throughout the inoculation periods, regardless of the avocado phenological stage. In temperature-dependent growth and infection studies, growth of three points could vary during the growing season. Botryosphaeriaceae grown was higher between 20 and 30°C, but only Lasiodiplodia theobromae significantly grew and caused external lesions at 35°C. Lasiodiplodia theobromae also grew more on perseitol-amended media, all indicating its adaptation to warmer temperatures and capacity in metabolizing the avocado-produced sugar. Overall, this study extended our knowledge of the prevalence, identity, and pathogenicity of Botryosphaeriaceae on avocado cultivars, which will be useful to tailor management strategies.

Botryosphaerialean fungi associated with woody oil plants cultivated in Sichuan Province, China

Woody oil plants are important economic trees which are widely cultivated and distributed throughout China. Surveys conducted during 2020 and 2021 on several woody oil plantations from five regions of Sichuan Province, China, revealed a high diversity of Botryosphaerialean fungi. The identification of 50 botryosphaeriaceous isolates was carried out based on both morphology and multi-gene phylogenetic analysis of internal transcribed spacer region (ITS), translation elongation factor 1-alpha gene (tef1) and β-tubulin gene (tub2). This allowed the identification of twelve previously known Botryosphaeriales species: Aplosporellaprunicola, A.ginkgonis, Barriopsistectonae, Botryosphaeriadothidea, Bo.fabicerciana, Diplodiamutila, Di.seriata, Dothiorellasarmentorum, Neofusicoccumparvum, Sardiniellaguizhouensis, Sphaeropsiscitrigena, and Sp.guizhouensis, and four novel species belonging to the genera Diplodia and Dothiorella, viz. Di.acerigena, Di.pistaciicola, Do.camelliae and Do.zanthoxyli. The dominant species isolated across the surveyed regions were Botryosphaeriadothidea, Sardiniellaguizhouensis and Diplodiamutila, representing 20%, 14% and 12% of the total isolates, respectively. In addition, most isolates were obtained from Pistaciachinensis (14 isolates), followed by Camelliaoleifera (10 isolates). The present study enhances the understanding of Botryosphaeriales species diversity on woody oil plants in Sichuan Province, China.

Neofusicoccum cryptomeriae sp. nov. and N. parvum Cause Stem Basal Canker of Cryptomeria japonica in China

Cryptomeria japonica D. Don is a coniferous tree species widely grown in southern China for its high ornamental value. Recently, during disease surveys in China, a symptom of dieback occurred on C. japonica in Nanjing, Jiangsu Province, China. A total of 130 trees were surveyed and more than 90% showed the same symptom. The crowns of affected trees were brown when viewing from a distance, and the bark showed no difference from the healthy ones. In this study, 157 isolates were isolated from the 3 affected plants of C. japonica, and based on the living culture on PDA, the fungal isolates were preliminarily divided into 6 groups. Thirteen representative isolates were selected for the pathogenicity test, and seven of them showed obvious pathogenicity on C. japonica, causing stem basal canker. These isolates were identified based on comparisons of the DNA sequences of the internal transcribed spacer regions (ITS), partial translation elongation factor 1-alpha (tef1), β-tubulin (tub2), and DNA-directed RNA polymerase II subunit (rpb2) and combined with their morphological characteristics. Results showed that these seven isolates belong to two taxa in Neofusicoccum, including a species new to science. The new species, Neofusicoccum cryptomeriae, was hereby described and illustrated. The other species was N. parvum. Both species were pathogens of stem basal canker of Cryptomeria japonica.

Botryosphaeriaceae gene machinery: Correlation between diversity and virulence

The Botryosphaeriaceae family comprises numerous fungal pathogens capable of causing economically meaningful diseases in a wide range of crops. Many of its members can live as endophytes and turn into aggressive pathogens following the onset of environmental stress events. Their ability to cause disease may rely on the production of a broad set of effectors, such as cell wall-degrading enzymes, secondary metabolites, and peptidases. Here, we conducted comparative analyses of 41 genomes representing six Botryosphaeriaceae genera to provide insights into the genetic features linked to pathogenicity and virulence. We show that these Botryosphaeriaceae genomes possess a large diversity of carbohydrate-active enzymes (CAZymes; 128 families) and peptidases (45 families). Botryosphaeria, Neofusicoccum, and Lasiodiplodia presented the highest number of genes encoding CAZymes involved in the degradation of the plant cell wall components. The genus Botryosphaeria also exhibited the highest abundance of secreted CAZymes and peptidases. Generally, the secondary metabolites gene cluster profile was consistent in the Botryosphaeriaceae family, except for Diplodia and Neoscytalidium. At the strain level, Neofusicoccum parvum NpBt67 stood out among all the Botryosphaeriaceae genomes, presenting a higher number of secretome constituents. In contrast, the Diplodia strains showed the lowest richness of the pathogenicity- and virulence-related genes, which may correlate with their low virulence reported in previous studies. Overall, these results contribute to a better understanding of the mechanisms underlying pathogenicity and virulence in remarkable Botryosphaeriaceae species. Our results also support that Botryosphaeriaceae species could be used as an interesting biotechnological tool for lignocellulose fractionation and bioeconomy.

Identification and pathogenicity of six fungal species causing canker and dieback disease on golden rain tree in Beijing, China

Golden rain trees (Koelreuteria paniculata) are largely cultivated because of their important ornamental, medicinal, and economic value. However, they are affected by canker and dieback disease to a large extent. To determine the fungi associated with canker and dieback disease of golden rain trees, isolations were obtained from diseased branches and twigs during 2019 and 2020 in greenbelts and nurseries in Beijing, China. Isolates were identified as six species (Allocryptovalsa castaneicola, Botryosphaeria dothidea, Cytospora koelreutericola sp. nov., Dothiorella acericola, Eutypella citricola, and Peroneutypa scoparia) based on morphological features and phylogenetic analyses of ITS, act, rpb2, tef1-α, and tub2. The results of pathogenicity tests indicated that all fungi produced discoloration and Botryosphaeria dothidea was highly aggressive to golden rain tree. In conclusion, this study explored the taxonomy, phylogeny, and pathogenicity of different fungal species associated with canker and dieback disease on golden rain tree and provided fundamental knowledge to improve disease management.

First report of Diplodia mutila causing canker and branch dieback of walnut trees in Xinjiang, China

Walnut (Juglans regia L.) has become an important economic fruit tree in China. In April 2022, branch dieback was observed in 15-year-old walnut trees (cv Wen 185) in a commercial orchard in Aksu, Xinjiang, China (40°21'55''N, 80°1'48''E), with an incidence of 2% (4 out of 200 trees) of affected trees. The symptoms observed, included depressed and shrunken cankers, twigs and branches dieback. Cross-sections of diseased branches revealed dark-brown wedge-shaped lesions. To isolate the potential causal pathogen, four specimens were isolated from diseased branches, and small pieces taken from the edge of canker samples (0.5 × 0.5 cm), were disinfected by immersion in 75% ethanol for 30 s and 2% NaClO solution for 3 min, and rinsed three times with sterile water. The disinfected wood samples were then placed on potato dextrose agar (PDA) and incubated in the dark at 25°C for 2-3 days. Then, we applied the mycelial tip purification method and repeated this purification process until a single colony was formed. Four pure isolates (3-1-51A, W-2-54, K-1-43A, K-1-43B) developed white to white-gray fast-growing colonies with abundant aerial mycelium after seven days at 25°C on PDA and gradually became dark olive green over subsequent growth stages. Conidia production was then induced on 2% w/v water agar containing sterilized pine needles under near-U/V light (Alves et al., 2004). The conidia were initially hyaline, thick-walled, oblong to ovoid with one septum and a size range of 19.47-24.16 × 9.78-13.51 µm (n = 40). Based on morphological characteristics these isolates were tentatively identified as Diplodia mutila (Fr.) Mont. (Alves et al., 2004).To confirm the pathogen identified, the representative isolate 3-1-51A was amplified and sequenced using specific primer pairs (ITS1/ITS4, EF1-986/EF1-728E, BT2a/BT2b) to the internal transcribed spacer (ITS), translation elongation factor 1-alpha (TEF1-α), and beta-tubulin (TUB) (White et al. 1990; Carbone and Kohn 1999; O' Donnell and Cigelnik 1997), respectively. The sequences showed 100% similarity to two D. mutila strains CBS230.30 and CBS112553. Maximum likelihood analysis was performed based on a concatenated dataset (ITS + TEF1-α + TUB) gene using MEGA 11. 0 and isolate 3-1-51A formed a single clade with the reference ex-type of D. mutila. The isolate 3-1-51A was deposited into GenBank as OP006733, OP373140, and OP373139 for ITS, TEF1-α, and TUB, respectively. To fulfill Koch's postulates, pathogenicity tests were performed using isolate 3-1-51A on one-year-old healthy walnut branches cv. Wen 185 of walnut trees (n=5). Five twigs of healthy walnut branches were cleaned, submerged in 1% NaClO for 15 minutes and then dried. Then, a sterile hole punch (5mm in diameter) was used to create a wound in the middle of each walnut branch, and placing mycelial plugs(3 days old; 5 mm in diameter) and sealed with parafilm. An equal number of twigs inoculated with sterile agar plugs served as controls. On the 7th day after inoculation, dark brown coloration was developed on the branches with symptoms of shrinkage dryness, and dieback. D. mutila isolate was re-isolated only from the inoculated branches. In negative control twigs, lesions and re-isolated were absent, thus fulfilling Koch's postulates. D. mutila has been previously reported causing canker and branch dieback in walnut trees in Chile (Díaz et al. 2018) and California (Chen et al. 2014). Previously, D. seriata (Zhang et al. 2017), Botryosphaeria dothidea (Guo et al. 2016), Lasiodiplodia pseudotheobromae (Guo et al. 2016), Dothiorella gregaria (Liu et al. 1986) and Neofusicoccum parvum (Yu et al. 2015) have been identified on walnut trees in China. To our knowledge, this is the first report of canker and branch dieback caused by D. mutila in walnut trees in Xinjiang, China. Further studies are now required to better understand the etiology of canker and branch dieback on walnut trees from different areas in China.

Isolation, molecular characterization and first report of Dothiorella gregaria associated with fruit rot of walnuts of Jammu and Kashmir, India

Walnuts are known for their high levels of antioxidants, which are linked to various health benefits. However, challenges related to distribution and storage, as well as the risk of fungal infections, can affect the quality of walnut kernels. Fungal pathogens from the Botryosphaeriaceae family, including Dothiorella species and Diplodia species, can damage fruit and reduce its antioxidant content. To comprehend the cause of fruit rot in walnuts, Dothiorella gregaria isolates were studied using polyphasic methods, including multiple gene sequences and morphological identification, as well as analysis of polyphenol content and pathogenicity. The walnuts kernels purchased from market places of Jammu and Kashmir (J&K), India were observed to be affected by Dothiorella gregaria species causing the quality detoriation and decrease in polyphenol content thus undeniably with decreased antioxidant properties. D. gregaria Infected walnut kernels were having some brown and black spots and some were having white mycelial growth and however, most samples were asymptomatic. Pathogenicity testing revealed that the pathogen was able to develop all the symptoms under experimental conditions and the reisolated pathogen was morphologically similar to D. gregaria. The samples infected with this pathogen showed considerable decrease in polyphenol content, 10.9 ± 2.66 mgGAE/g (mean ± standard deviation) thus decreased antioxidant quality as compared to the samples which showed zero incidence of this pathogen, 52.50 ± 4.27 mgGAE/g (mean ± standard deviation). Furthermore, the pathogen was studied using polyphasic approach involving morphological, molecular and phylogenetic analysis. Combined nucleotide dataset of nuclear ribosomal ITS and tef1-α revealed that Dothiorella gregaria (NY6) formed a clade with Dothiorlla iberica (MAEC33), Dothiorella sarmentorium (MAEC28) and Dothiorella iberica (CAA905) strains with 83% bootstrap support. Besides, we observed six nucleotide changes, four were insertions or deletions and two were substitutions in the 502-bp region of the ITS rRNA gene when we compared our isolate to the most equivalent sequences submitted to NCBI GenBank. This is the first report of Dothiorella gregaria affecting walnuts purchased from various markets in J&K, India, causing fruit rot in walnuts after harvest. Given that local farmers store and export walnuts, it could pose an emerging threat to their livelihood. Thus, creating post-harvesting interventions for D. gregaria and knowing more about the fruit rot in walnuts can be benefited from morphological and molecular identification using several gene loci, genetic variability in the ITS rRNA gene, and total phenol analysis.

Pest categorisation of Lasiodiplodia pseudotheobromae

The EFSA Plant Health Panel performed a pest categorisation of Lasiodiplodia pseudotheobromae, a clearly defined fungus of the family Botryosphaeriaceae, which was first described in 2008 as a cryptic species within the L. theobromae complex. The pathogen affects a wide range of woody perennial crops and ornamental plants causing root rot, damping-off, leaf spots, twig blight, cankers, stem-end rot, gummosis, branch dieback and pre- and post-harvest fruit rots. Lasiodiplodia pseudotheobromae is present in Africa, Asia, North and South America and Oceania and has also been reported from Spain with a restricted distribution. However, there is uncertainty on the status of the pathogen worldwide and in the EU because in the past, when molecular tools (particularly multigene phylogenetic analysis) were not available, the pathogen might have been misidentified as L. theobromae. Lasiodiplodia pseudotheobromae is not included in Commission Implementing Regulation (EU) 2019/2072 and there are no interceptions in the EU. Because of the very wide host range of the pathogen, this pest categorisation focused on those hosts for which there is robust evidence that the pathogen was formally identified by a combination of morphology, pathogenicity and multilocus sequence analysis. Plants for planting, including seeds, fresh fruits and bark and wood of host plants as well as soil and other plant-growing media are the main pathways for the further entry of the pathogen into the EU. Host availability and climate suitability factors occurring in parts of the EU are favourable for the further establishment of the pathogen. In the area of its present distribution, including Spain, the pathogen has a direct impact on cultivated hosts. multilocus measures are available to prevent the further introduction and spread of the pathogen into the EU. Lasiodiplodia pseudotheobromae satisfies the criteria that are within the remit of EFSA to assess for this species to be regarded as potential Union quarantine pest.

Effects of Cultivar Susceptibility, Branch Age, and Temperature on Infection by Botryosphaeriaceae and Diaporthe Fungi on English Walnut (Juglans regia)

Botryosphaeriaceae and Diaporthe fungi have been described as the main causal agents of branch dieback and shoot blight of English walnut (Juglans regia L.). To date, the effects of biotic and abiotic factors on disease development on this host are still poorly understood. Thus, the main goal of this study was to evaluate the effects of cultivar, shoot-branch age, and temperature on infection by Botryosphaeriaceae and Diaporthe fungi on English walnut. The susceptibility of eight commercial cultivars was evaluated against three Botryosphaeriaceae and two Diaporthe species. For the remaining experiments, shoots or branches of 'Chandler' were used. An initial experiment evaluating two inoculation methods was conducted, with inoculation with a mycelial plug being more consistent and useful than conidial suspension inoculation. Cultivar susceptibility varied depending on the fungal species, with 'Chandler' being among the most tolerant cultivars for shoot infection. One-year-old shoots were significantly more sensitive for both Neofusicoccum parvum and Diaporthe neotheicola in comparison with 2- to 4-year-old branches. The effect of temperature on shoot infection was evaluated under 5, 10, 15, 20, 25, 30, and 35°C. Lesion development was significantly higher for N. parvum isolates than for D. neotheicola isolates at all temperatures evaluated, with optimum temperature of shoot infection being ∼26°C for N. parvum and ∼21°C for D. neotheicola.

Morphology and phylogeny of ascomycetes associated with walnut trees (Juglans regia) in Sichuan province, China

In Sichuan province, walnuts, consisting of Juglans regia, Juglans sigillata, and the hybrid J. regia × J. sigillata, are commercially important edible nuts, and J. regia is the most widespread plant. To date, the diversity and distribution of fungi inhabiting on Juglans have not received enough attention, although there have been studies focusing on pathogens from fruit and stem. In order to update the checklist of fungi associated with Sichuan walnuts, a survey on fungi associated with the three Juglans species from 15 representative regions in Sichuan was conducted. In this article, ten fungi distributed in two classes of Ascomycota (Dothideomycetes and Sordariomycetes) were described based on morpho-molecular analyses, and two novel species, Neofusicoccum sichuanense and Sphaerulina juglandina, a known species of Ophiognomonia leptostyla, and seven new hosts or geographical records of Cladosporium tenuissimum, Diatrypella vulgaris, Helminthosporium juglandinum, Helminthosporium velutinum, Loculosulcatispora hongheensis, Periconia byssoides, and Rhytidhysteron subrufulum were included. Morphological descriptions and illustrations of these fungi are provided.

Effects of Temperature on Development of Canker-Causing Pathogens in Almond and Prune

Between 2000 and 2020, canker diseases of nut and stone fruit trees have become very widespread and severe in California. This study determined the effects of temperature on the development of canker-causing pathogens of almond and prune. Five pathogen taxa, Botryosphaeria dothidea, Cytospora leucostoma, Diaporthe (Phomopsis) neotheicola, Lasiodiplodia citricola, and Neofusicoccum mediterraneum, were used. Colony growth on medium and canker lesion development on detached shoots were measured at 10, 15, 20, 25, 30, and 35°C. The effects of temperature on colony growth differed among different pathogen taxa, although 25°C was the optimal temperature for most of the pathogens tested. The patterns of lesion growth as response to temperature were different among the different pathogens and tree crops. On almond, the highest growth rates appeared at 30°C for B. dothidea and L. citricola, but at 20°C for N. mediterraneum. The growth rates for C. leucostoma were lower than those of the other three pathogen taxa, with the highest rates recorded at 25°C. However, on prune, C. leucostoma showed greater lesion growth rates at different temperatures than the other pathogen taxa and maximum growth at 30 to 35°C. Similar trends were observed for L. citricola. The growth rates of B. dothidea and N. mediterraneum were comparatively lower than those of C. leucostoma and L. citricola.

Comparative Profiling of Wood Canker Pathogens from Spore Traps and Symptomatic Plant Samples Within California Almond and Walnut Orchards

Fungi causing wood canker diseases are major factors limiting productivity and longevity of almond and walnut orchards. The goal of this study was to compare pathogen profiles from spore traps with those of plant samples collected from symptomatic almond and walnut trees and assess if profiles could be influenced by orchard type and age, rainfall amount and frequency, and/or neighboring trees. Three almond orchards and one walnut orchard with different characteristics were selected for this study. Fungal inoculum was captured weekly from nine trees per orchard using a passive spore-trapping device, during a 30-week period in the rainy season (October to April) and for two consecutive years. Fungal taxa identified from spore traps were compared with a collection of fungal isolates obtained from 61 symptomatic wood samples collected from the orchards. Using a culture-dependent approach coupled with molecular identification, we identified 18 known pathogenic species from 10 fungal genera (Ceratocystis destructans, Collophorina hispanica, Cytospora eucalypti, Diaporthe ampelina, Diaporthe chamaeropis/rhusicola, Diaporthe eres, Diaporthe novem, Diplodia corticola, Diplodia mutila, Diplodia seriata, Dothiorella iberica, Dothiorella sarmentorum, Dothiorella viticola, Eutypa lata, Neofusicoccum mediterraneum, Neofusicoccum parvum, Neoscytalidium dimidiatum, and Pleurostoma richardsiae), plus two unidentified Cytospora and Diaporthe species. However, only four species were identified with both methods (Diplodia mutila, Diplodia seriata, Dothiorella Iberica, and E. lata), albeit not consistently across orchards. Our results demonstrate a clear disparity between the two diagnostic methods and caution against using passive spore traps to predict disease risks. In particular, the spore trap approach failed to capture: insect-vectored pathogens such as Ceratocystis destructans that were often recovered from almond trunk and scaffold; Diaporthe chamaeropis/rhusicola commonly isolated from wood samples likely because Diaporthe species have a spatially restricted dispersal mechanism, as spores are exuded in a cirrus; and pathogenic species with low incidence in wood samples such as P. richardsiae and Collophorina hispanica. We propose that orchard inoculum is composed of both endemic taxa that are characterized by frequent and repeated trapping events from the same trees and isolated from plant samples, as well as immigrant taxa characterized by rare trapping events. We hypothesize that host type, orchard age, precipitation, and alternative hosts at the periphery of orchards are factors that could affect pathogen profile. We discuss the limitations and benefits of our methodology and experimental design to develop guidelines and prediction tools for fungal wood canker diseases in California orchards.

Diversity of Botryosphaeriaceae and Diaporthe Species Associated with Postharvest Apple Fruit Decay in Serbia

Family Botryosphaeriaceae and the genus Diaporthe (family Diaporthaceae) represent diverse groups of plant pathogens, which include causal agents of leaf spot, shoot blight, branch and stem cankers, dieback, and pre- and postharvest apple fruit decay. Apple fruit with symptoms of light to dark brown decay were collected during and after harvest from 2016 to 2018. Thirty selected isolates, on which pathogenicity was confirmed, were identified and characterized based on multilocus phylogeny and morphology. Five species from the family Botryosphaeriaceae and two from the genus Diaporthe (fam. Diaporthaceae) were discovered. The most commonly isolated was Diplodia seriata followed by Botryosphaeria dothidea. In this work, Diaporthe rudis is described as a new postharvest pathogen of apple fruit. Diplodia bulgarica, Diplodia sapinea, Neofusicoccum yunnanense, and Diaporthe eres are initially described as postharvest apple and D. sapinea as postharvest quince and medlar fruit pathogens in Serbia. Because species of the family Botryosphaeriaceae and the genus Diaporthe are known to cause other diseases on their hosts, have an endophytic nature, and have a wide host range, findings from this study imply that they may become a new challenge for successful fruit production.

Characterization and Pathogenicity of Diplodia, Lasiodiplodia, and Neofusicoccum Species Causing Botryosphaeria Canker and Dieback of Apple Trees in Central Chile

In recent years, the number of apple trees affected by Botryosphaeria cankers and dieback has considerably increased in central Chile. This study aimed to identify the species of Botryosphaeriaceae associated with canker and dieback symptoms, estimate disease incidence and distributions, and study their pathogenicity and virulence on apple and other fruit crops. A field survey of 34 commercial orchards of apple (7 to 30 years old) was conducted in 16 localities, obtaining 270 symptomatic branch and trunk samples in 2017 and 2018 growing seasons. The incidence of Botryosphaeria canker and dieback ranged between 5 and 40%, and a total of 255 isolates of Botryosphaeriaceae spp. were obtained from 238 cankers. Morphological identification along with phylogenetic studies of the internal transcribed spacer (ITS) region (ITS1-5.8S-ITS2) of the rDNA, part of the translation elongation factor 1-α (tef1-α), and part of the β-tubulin (tub2) genes allowed us to identify Diplodia mutila (n = 49 isolates), D. seriata (n = 136 isolates), Lasiodiplodia theobromae (n = 16 isolates), and Neofusicoccum arbuti (n = 54 isolates). L. theobromae was isolated mainly from apple dieback from northern localities. All pathogens tested were pathogenic, causing canker and dieback symptoms on lignified twigs of apple, pear, walnut, and green grapevine shoots in the field. Isolates of N. arbuti were the most virulent, reproducing more severe cankers on the lignified tissues inoculated. This study reports, for the first time, D. mutila and L. theobromae associated with Botryosphaeria canker and dieback in Chile, and it is the first description of N. arbuti causing apple dieback worldwide.

Etiology of Septoria Leaf Spot of Pistachio in Southern Spain

Septoria leaf spot (SLS) is the most prevalent disease of pistachio (Pistacia vera L.) in Spain. To elucidate its etiology, 22 samples of pistachio leaves showing SLS symptoms were collected mainly from 1993 to 2018 across southern Spain. Affected leaves from terebinth (P. terebinthus) were also collected for comparative purposes. Six Septoria-like isolates were recovered from pistachio leaves. They were identified as S. pistaciarum by sequencing internal transcribed spacers, partial RNA polymerase II second largest subunit locus, and 28S ribosomal RNA genes. The phenotypic characteristics of conidia and colonies were evaluated, confirming the identity of S. pistaciarum. Conidia were solitary, hyaline, and straight to curved. Large differences in length were observed between conidia from leaf samples, with those from terebinth being slightly larger than those from pistachio. Colonies showed slow mycelial growth on potato dextrose agar (PDA). The effect of temperature on conidial germination and mycelial growth was evaluated in vitro on PDA. For both characters, the optimum temperature was approximately 19 to 20°C. Eight culture media were tested, with oatmeal agar and Spezieller Nährstoffarmer agar showing the highest mycelial growth and pistachio leaf agar (PLA) showing the highest sporulation. A specific culture medium integrating lyophilized-powdered pistachio leaves into diluted PDA improved sporulation compared with PLA. Pathogenicity tests were conducted by inoculating detached and in planta pistachio and terebinth leaflets with conidial suspensions. Typical symptoms of SLS and cirri of S. pistaciarum developed at 10 and 21 days after inoculation, respectively, in both hosts. To our knowledge, this is the first report of S. pistaciarum causing SLS in pistachio and terebinth in Spain.

Morphology Characterization, Molecular Identification, and Pathogenicity of Fungal Pathogen Causing Kaffir Lime Leaf Blight in Northern Thailand

Thailand is known to be the largest producer of kaffir lime leaf products in the global market. In 2021, leaf blight was found on kaffir lime plants (Citrus hystrix DC.) in Lamphun Province of northern Thailand. This disease has been associated with significant economic losses. However, there have been no prior reports of leaf blight on kaffir lime plants in Thailand or anywhere else in the world. In this study, causal fungi were isolated from lesions of kaffir lime plants and a total of three fungal isolates were obtained. All causal fungi were identified as Lasiodiplodia chinensis based on morphological characteristics and the phylogenetic analysis of combined sequences of the internal transcribed spacer (ITS) of ribosomal DNA, the translation elongation factor 1-alpha (tef-1), β-tubulin (tub), and RNA polymerase II subunit (rbp2) genes. Pathogenicity tests were conducted and the results revealed that all isolated fungi caused symptoms of leaf blight on inoculated leaves. This outcome was similar to symptoms that naturally occur and have been observed in the field. This is the first report on kaffir lime leaf blight caused by L. chinensis. Our study will provide information of high value for the development of effective strategies for the monitoring and prevention of this disease.

Characterization of grapevine fungal canker pathogens Fatty Acid Methyl Ester (FAME) profiles

Fatty acid methyl ester (FAME) analyses can be useful for distinguishing microbial species. This study conducted FAME analyses on 14 fungal species known to cause grapevine trunk diseases. FAME profiles were dominated by oleic acid, albeit profiles were characteristic enough to separate species. Discriminant analyses suggested that palmitoleic acid/sapienic acid, pentadecylic acid, and an unsaturated 17-carbon fatty acid (17:1ω8 c)could explain 79.8% of the variance in the profiles among species in the first three discriminant functions. FAME profile libraries were created for use in a commercialized software, which was able to accurately identify isolates to the species level, with a low rate (9.4%) of samples to be reassessed. Dendrograms created using neighbor-joining cluster analyses with data from FAME profiles were compared with those using internal transcribed spacer (ITS) region sequences. This revealed that FAME profiles, albeit useful for tentative species identification, should not be used for determining phylogenetic relationships because the dendrograms were significantly unconcordant. Regardless, these results demonstrated the potential of FAME analyses in quickly and initially identifying closely related fungal species or confirming conclusions from other species identification techniques that would require independent validation.

Pathogenicity Testing of Fungal Isolates Associated with Olive Trunk Diseases in South Africa

A recent olive trunk disease survey performed in the Western Cape Province, South Africa, identified several fungi associated with olive trunk disease symptoms, including species of Basidiomycota, Botryosphaeriaceae, Coniochaetaceae, Calosphaeriaceae, Diaporthaceae, Diatrypaceae, Phaeomoniellaceae, Phaeosphaeriaceae, Symbiotaphrinaceae, Togniniaceae, and Valsaceae. Many of the species recovered had not yet been reported from olive trees; therefore, the aim of this study was to determine their pathogenicity toward this host. Pathogenicity tests were first conducted on detached shoots to select virulent isolates, which were then used in field trials. During field trials, 2-year-old olive branches of 15-year-old trees were inoculated by inserting colonized agar plugs into artificially wounded tissue. Measurements were made of the internal lesions after 8 months. In total, 58 isolates were selected for the field trials. Species that formed lesions significantly larger than the control could be considered as olive trunk pathogens. These included Biscogniauxia rosacearum, Celerioriella umnquma, Coniochaeta velutina, Coniothyrium ferrarisianum, isolates of the Cytospora pruinosa complex, Didymocyrtis banksiae, Diaporthe foeniculina, Eutypa lata, Fomitiporella viticola, Neofusicoccum stellenboschiana, Neofusicoccum vitifusiforme, Neophaeomoniella niveniae, Phaeoacremonium africanum, Phaeoacremonium minimum, Phaeoacremonium oleae, Phaeoacremonium parasiticum, Phaeoacremonium prunicola, Phaeoacremonium scolyti, Phaeoacremonium spadicum, Pleurostoma richardsiae, Pseudophaeomoniella globosa, Punctularia atropurpurascens, Vredendaliella oleae, an undescribed Cytospora sp., Geosmithia sp., two undescribed Neofusicoccum spp., and four Xenocylindrosporium spp. Pseudophaeomoniella globosa can be regarded as one of the main olive trunk pathogens in South Africa because of its high incidence from olive trunk disease symptoms in established orchards and its high virulence in pathogenicity trials.

Evaluation of Pruning Wound Protection Products for the Management of Almond Canker Diseases in California

Almond trunk and branch canker diseases constitute a major cause of tree mortality in California. Numerous fungal pathogens have been associated with these canker diseases and pruning wounds act as major infection courts. Before this study, there were no products registered in California for the management of these diseases. In this study, fungicidal products including synthetic chemistries, biocontrols, paint, and a sealant were evaluated for preventing fungal pathogen infection via pruning wounds. In four field trials conducted over two dormant seasons, 16 pruning wound treatments were tested using handheld spray applications against five almond canker pathogens, namely Botryosphaeria dothidea, Neofusicoccum parvum, Cytospora sorbicola, Ceratocystis destructans, and Eutypa lata. The fungicide thiophanate-methyl (Topsin M; United Phosphorus, Bandra West, Mumbai, India) provided 82% overall disease prevention against four fungal pathogens. The biological control agent, Trichoderma atroviride SC1 (Vintec; Bi-PA, Londerzeel, Belgium), tested at three application rates, resulted in 90 to 93% protection of pruning wounds in field trials, and for individual pathogens ranged from 81 to 100% protection for the three rates. At the time of this publication, Vintec is being considered for registration as a biological control product for the prevention of almond canker diseases, while Topsin M is recommended to growers for the prevention of almond canker diseases. This research indicates that effective protection of pruning wounds from infection by almond canker pathogens can be achieved with a one-time spray application of thiophanate-methyl or the biocontrol T. atroviride SC1 (recommended 2 g/liter) after pruning.

Limited Evidence for Accumulation of Latent Infections of Canker-Causing Pathogens in Shoots of Stone Fruit and Nut Crops in California

Prevalence of latent infections of the canker-causing fungi Botryosphaeria dothidea and species of Cytospora, Diplodia, Lasiodiplodia, Neofusicoccum, and Phomopsis in young shoots of almond, prune, and walnut trees in California was studied to test the hypotheses that latent infections accumulate from current-season shoots to 1-year-old shoots in the orchard and there are distinct associations among pathogen taxa present as latent infections in the same shoot. Samples of newly emerged and 1-year-old shoots were periodically collected in each almond, prune, and walnut orchard for two growing seasons. A real-time quantitative PCR assay was used to quantify latent infection with three parameters: incidence, molecular severity, and latent infection index. Diplodia spp. were absent from most samples. For almond, Lasiodiplodia spp. and Cytospora spp. were detected with a maximum incidence >90%, while B. dothidea and Neofusicoccum spp. incidence was <20% in most cases. In prune orchards, the incidence levels of B. dothidea were >50% in most cases, while those of Cytospora spp. and Lasiodiplodia spp. were 30 to 60% and 30 to 100%, respectively. For walnut, many samplings showed higher incidence in 1-year-old (30 to 80%) than in newly emerged shoots (10 to 50%). Accumulation of latent infection between the two shoot age classes was detected in only a few cases. The percentages of samples showing coexistence of two, three, and four pathogen taxa in the same shoot were 20 to 25, <10, and <5%, respectively. Pairwise associations among pathogen taxa in the same shoot were significant in many cases.

Occurrence of Canker and Wood Rot Pathogens on Stone Fruit Propagation Material and Nursery Trees in the Western Cape of South Africa

Dieback and canker of young stone fruit trees can cause suboptimal growth and even death under severe conditions. One source of inoculum of canker pathogens could be through nursery trees harboring latent infections that would not be visible to inspections done according to the deciduous fruit scheme. The objectives of this study were to identify the canker and wood rot fungal pathogens present in nursery stone fruit trees as well as in propagation material and to evaluate their pathogenicity. Isolations were made from scion and rootstock propagation material and from certified nursery stone fruit trees. The plant material sampled did not have any external symptoms. The certified nursery trees when cross-sectioned displayed brown discoloration from the pruning wound, the bud union, and often the crown. Fungal species isolated were identified by sequencing of the relevant barcoding genes and phylogenetic analyses thereof. Canker- and wood rot-associated fungi were identified. Buds used for budding had low levels of infection, with 1.2% of dormant buds infected and 0.4% of green buds infected. The dormant rootstock shoots had a canker pathogen incidence of 6.2% before they were planted in the nursery fields and increased inasmuch as the ungrafted, rooted rootstock plants had 11.1% infection with canker and wood rot pathogens. Out of 1,080 nursery trees, the canker- and wood rot-associated fungi infected 21.8% of trees. The canker-causing pathogens that were isolated the most were Cadophora luteo-olivacea and Diplodia seriata. A low incidence of wood rot fungi was found, with only 1.5% of nursery trees infected. In total, 26 new reports of fungal species on stone fruit in South Africa were made. Of these, 22 have not been found on stone fruit worldwide. The pathogenicity trials' results confirmed the pathogenic status of these newly reported species. All of the isolates tested formed lesions significantly longer than the control, 4 months after wound inoculation of 2-year-old shoots of two plum orchards. Lasiodiplodia theobromae was the most virulent species on both plum cultivars. The results of this research showed that nursery stone fruit trees and propagation material can harbor latent infections. Different management practices need to be evaluated to prevent these infections to ensure healthier stone fruit nursery trees.

Identification and Pathogenicity of Diplodia, Neofusicoccum, Cadophora, and Diaporthe Species Associated with Cordon Dieback in Kiwifruit cultivar Hayward in Central Chile

Dieback symptoms associated with fungal trunk pathogens cause significant economic losses for farmers of kiwifruit and other woody fruit trees worldwide. This study represents the first attempt to identify and characterize the fungal trunk pathogens associated with cordon dieback disease of kiwifruit in central Chile. Field surveys were conducted throughout the main kiwifruit-growing regions in central Chile to determine the incidence and characterize the fungal trunk pathogens associated with cordon dieback of kiwifruit cultivar Hayward through morphological, molecular, and pathogenicity studies. A total of 250 cordon samples were collected and isolations were performed on 2% acidified potato dextrose agar (APDA) plus antibiotics and Igepal. The incidence of kiwifruit cordon dieback ranged between 5% and 85% in all surveyed areas in central Chile. A total of 246 isolates were isolated and identified using culture and morphological features belonging to three fungal taxa: Diaporthaceae spp. (Diaporthe ambigua and D. australafricana; n = 133 isolates); Botryosphaeriaceae spp. (Diplodia seriata and Neofusicoccum parvum; n = 89 isolates); and Ploettnerulaceae spp. (Cadophora luteo-olivacea and C. malorum; n = 24 isolates). These were identified using phylogenetics studies of the internal transcribed spacer (ITS) region (ITS1-5.8S-ITS2) of the rDNA, part of the β-tubulin gene (tub2), and part of the translation elongation factor 1-α gene (tef1-α). Isolates of N. parvum and D. seriata were the most virulent, causing internal brown lesions and dieback symptoms in attached green shoots, attached lignified canes, and young inoculated kiwifruits. This report is the first to describe D. seriata and C. luteo-olivacea associated with kiwifruit cordon dieback in Chile. It presents the first description of N. parvum causing kiwifruit dieback worldwide.

Phylogenomics of Plant-Associated Botryosphaeriaceae Species

The Botryosphaeriaceae is a fungal family that includes many destructive vascular pathogens of woody plants (e.g., Botryosphaeria dieback of grape, Panicle blight of pistachio). Species in the genera Botryosphaeria, Diplodia, Dothiorella, Lasiodiplodia, Neofusicoccum, and Neoscytalidium attack a range of horticultural crops, but they vary in virulence and their abilities to infect their hosts via different infection courts (flowers, green shoots, woody twigs). Isolates of seventeen species, originating from symptomatic apricot, grape, pistachio, and walnut were tested for pathogenicity on grapevine wood after 4 months of incubation in potted plants in the greenhouse. Results revealed significant variation in virulence in terms of the length of the internal wood lesions caused by these seventeen species. Phylogenomic comparisons of the seventeen species of wood-colonizing fungi revealed clade-specific expansion of gene families representing putative virulence factors involved in toxin production and mobilization, wood degradation, and nutrient uptake. Statistical analyses of the evolution of the size of gene families revealed expansions of secondary metabolism and transporter gene families in Lasiodiplodia and of secreted cell wall degrading enzymes (CAZymes) in Botryosphaeria and Neofusicoccum genomes. In contrast, Diplodia, Dothiorella, and Neoscytalidium generally showed a contraction in the number of members of these gene families. Overall, species with expansions of gene families, such as secreted CAZymes, secondary metabolism, and transporters, were the most virulent (i.e., were associated with the largest lesions), based on our pathogenicity tests and published reports. This study represents the first comparative phylogenomic investigation into the evolution of possible virulence factors from diverse, cosmopolitan members of the Botryosphaeriaceae.

Further Investigation on Limb Dieback of Fig (Ficus carica) Caused by Neoscytalidium dimidiatum in California

Fig limb dieback is a cosmopolitan disease caused by Neoscytalidium dimidiatum (Botryosphaeriaceae), characterized by branch and shoot cankers, discoloration of woody tissues, and dieback. The present study investigated the etiology of the disease in California that seems to have become prevalent among fig orchards in the last several years. During orchard surveys in Fresno, Kern, and Madera Counties over 3 years, we isolated consistently and evaluated the pathogenicity of N. dimidiatum under laboratory and field conditions. The effect of summer and winter pruning on the disease severity and the effects of different environmental and mechanical stresses, such as sunburn and wounding by mallets, were assayed. In addition, the susceptibility of six different cultivars and the effects of eradicating cankered shoots from the fig trees as a method to combat the spread of the disease were studied. Pathogenicity tests demonstrated that N. dimidiatum induces cankers on fig, mainly on wounded shoots. Results from the remaining experiments revealed that summer infection leads to more severe canker lesions than those induced by winter infection and that stressed shoots are more susceptible to infection than nonstressed shoots. 'Brown Turkey', 'Conadria', and 'Calimyrna' cultivars (all nonpersistent figs, i.e., needing pollination for fruit development) were less susceptible than the more susceptible 'Kadota', 'Sierra', and 'Black Mission' (all persistent figs, i.e., not needing pollination for fruit development). Canker removal from the orchard seems to be a good agronomic practice to avoid the spread of disease.

Fungal Pathogens Associated With Canker Diseases of Almond in California

Almond canker diseases are destructive and can reduce the yield as well as the lifespan of almond orchards. These diseases may affect the trunk and branches of both young and mature trees and can result in tree death soon after orchard establishment in severe cases. Between 2015 and 2018, 70 almond orchards were visited throughout the Central Valley of California upon requests from farm advisors for canker disease diagnosis. Two major canker diseases were identified, including Botryosphaeriaceae cankers and Ceratocystis canker. In addition, five less prevalent canker diseases were identified, including Cytospora, Eutypa, Diaporthe, Collophorina, and Pallidophorina canker. Seventy-four fungal isolates were selected for multilocus phylogenetic analyses of internal transcribed spacer region ITS1-5.8S-ITS2 and part of the translation elongation factor 1-α, β-tubulin, and glyceraldehyde 3-phosphate dehydrogenase gene sequences; 27 species were identified, including 12 Botryosphaeriaceae species, Ceratocystis destructans, five Cytospora species, Collophorina hispanica, four Diaporthe species, two Diatrype species, Eutypa lata, and Pallidophorina paarla. The most frequently isolated species were Ceratocystis destructans, Neoscytalidium dimidiatum, and Cytospora californica. Pathogenicity experiments on almond cultivar Nonpareil revealed that Neofusicoccum parvum, Neofusicoccum arbuti, and Neofusicoccum mediterraneum were the most virulent. Botryosphaeriaceae cankers were predominantly found in young orchards and symptoms were most prevalent on the trunks of trees. Ceratocystis canker was most commonly found in mature orchards and associated with symptoms found on trunks or large scaffold branches. This study provides a thorough examination of the diversity and pathogenicity of fungal pathogens associated with branch and trunk cankers of almond in California.

Refined families of Dothideomycetes: orders and families incertae sedis in Dothideomycetes

Numerous new taxa and classifications of Dothideomycetes have been published following the last monograph of families of Dothideomycetes in 2013. A recent publication by Honsanan et al. in 2020 expanded information of families in Dothideomycetidae and Pleosporomycetidae with modern classifications. In this paper, we provide a refined updated document on orders and families incertae sedis of Dothideomycetes. Each family is provided with an updated description, notes, including figures to represent the morphology, a list of accepted genera, and economic and ecological significances. We also provide phylogenetic trees for each order. In this study, 31 orders which consist 50 families are assigned as orders incertae sedis in Dothideomycetes, and 41 families are treated as families incertae sedis due to lack of molecular or morphological evidence. The new order, Catinellales, and four new families, Catinellaceae, Morenoinaceae Neobuelliellaceae and Thyrinulaceae are introduced. Seven genera (Neobuelliella, Pseudomicrothyrium, Flagellostrigula, Swinscowia, Macroconstrictolumina, Pseudobogoriella, and Schummia) are introduced. Seven new species (Acrospermum urticae, Bogoriella complexoluminata, Dothiorella ostryae, Dyfrolomyces distoseptatus, Macroconstrictolumina megalateralis, Patellaria microspora, and Pseudomicrothyrium thailandicum) are introduced base on morphology and phylogeny, together with two new records/reports and five new collections from different families. Ninety new combinations are also provided in this paper.

Variation in Botryosphaeriaceae from Eucalyptus plantations in YunNan Province in southwestern China across a climatic gradient

The Botryosphaeriaceae accommodates many important pathogens of woody plants, including Eucalyptus. Recently, Botryosphaeriaceae were isolated from diseased plant parts from surveys of Eucalyptus plantations in the YunNan Province, China. The aims of this study were to identify these Botryosphaeriaceae isolates and to evaluate their pathogenicity to Eucalyptus. A total of 166 isolates of Botryosphaeriaceae were obtained from six regions in the YunNan Province, of which 76 were from Eucalyptus urophylla × E. grandis hybrids, 49 from E. globulus trees, and 41 isolates were from other unknown Eucalyptus species or hybrids. Isolates were identified by comparing DNA sequences of the internal transcribed spacer ribosomal RNA locus (ITS), partial translation elongation factor 1-alpha (tef1), β-tubulin 2 (tub2) and DNA-directed RNA polymerase II subunit (rpb2) genes, and combined with their morphological characteristics. Eleven species were identified, including Botryosphaeria fusispora, B. wangensis, Lasiodiplodia pseudotheobromae, Neofusicoccum kwambonambiense, N. parvum, and six novel species described as B. puerensis, N. dianense, N. magniconidium, N. ningerense, N. parviconidium and N. yunnanense. The dominant species across the regions were N. yunnanense, N. parvum and B. wangensis, representing 31.3, 25.3 and 19.9% of the total isolates, respectively. Species diversity and composition changed across the different climatic zones, despite their relatively close geographic proximity and the fact that some of the species have a global distribution. All the Botryosphaeriaceae species were pathogenic to one-year-old plants of an E. urophylla × E. grandis clone and E. globulus seed-derived plants, but showed significant inter- and intra-species variation in aggressiveness amongst isolates. The study provides a foundation for monitoring and management of Botryosphaeriaceae through selection and breeding of Eucalyptus in the YunNan Province of southwestern China.

Water Stress Enhances the Progression of Branch Dieback and Almond Decline under Field Conditions

Branch dieback and tree decline have been described as a common complex disease worldwide in woody crops, with Botryosphaeriaceae and Diaporthaceae being considered the most frequent fungi associated with the disease symptoms. Their behaviour is still uncertain, since they are considered endophytes becoming pathogenic in weakened hosts when stress conditions, such as water deficiency occur. Therefore, the main goal of this study was to determine if water stress enhances general decline on weakened almond trees subjected to different irrigation treatments under natural field conditions. In parallel, the occurrence of fungal species associated with almond decline was also determined in relation to disease progression by fungal isolation, and morphological and molecular based-methods. The symptoms of branch dieback and general decline were observed over time, mainly in the experimental plots subjected to high water deficiency. Botryosphaeriaceae were the most consistently isolated fungi, and Botryosphaeria dothidea was the most frequent. Collophorina hispanica was the second most frequent species and Diaporthe and Cytospora species were isolated in a low frequency. Most of them were recovered from both asymptomatic and symptomatic trees, with their consistency of isolation increasing with the disease severity. This work reveals the need to elucidate the role of biotic and abiotic factors which increase the rate of infection of fungal trunk pathogens, in order to generate important knowledge on their life cycle.

Lasiodiplodia mitidjana sp. nov. and other Botryosphaeriaceae species causing branch canker and dieback of Citrus sinensis in Algeria

Several Botryosphaeriaceae species are known to occur worldwide, causing dieback, canker and fruit rot on various hosts. Surveys conducted in ten commercial citrus orchards in the northern region of Algeria revealed five species of Botryosphaeriaceae belonging to three genera associated with diseased trees. Morphological and cultural characteristics as well as phylogenetic analyses of the internal transcribed spacer (ITS) region and the translation elongation factor 1-alpha (tef1-α) identified Diplodia mutila, Diplodia seriata, Dothiorella viticola, Lasiodiplodia mediterranea and a novel species which is here described as Lasiodiplodia mithidjana sp. nov.. Of these, L. mithidjana (14.1% of the samples) and L. mediterranea (13% of the samples) were the most widespread and abundant species. Pathogenicity tests revealed that L. mediterranea and D. seriata were the most aggressive species on citrus shoots. This study highlights the importance of Botryosphaeriaceae species as agents of canker and dieback of citrus trees in Algeria.

Stem Canker on Cyclocarya paliurus Is Caused by Botryosphaeria dothidea

Cyclocarya paliurus, an important endangered plant in China, has considerable medicinal, timber, and horticultural value. However, little is known about diseases that affect its health. In recent years, stem canker diseases on C. paliurus have been observed frequently in newly established nurseries in Jiangsu Province, China. Symptomatic trees showed elliptical, sunken lesions on the bark, with internal discoloration, leading to enlarging cankers with delineated margins. Pathogenicity tests with fungi isolated from symptomatic samples reproduced typical canker symptoms on both detached branches and potted plants of C. paliurus. Moreover, conidia from pycnidia of isolate ZB-23 could also cause stem canker on C. paliurus. Through combined morphological observation and DNA sequences of ITS region, β-tubulin, and translation elongation factor 1-α genes, the pathogen was identified as Botryosphaeria dothidea. Multigene maximum likelihood and maximum parsimony phylogenetic analyses further supported the identification of the pathogen. To our knowledge, this is the first report of B. dothidea causing stem canker on C. paliurus in China.

Fungal Trunk Pathogens Associated With Juglans regia in the Czech Republic

Juglans regia L. (English walnut) trees with cankers and dieback symptoms were observed in two regions in the Czech Republic. Isolations were made from diseased branches. In total, 138 fungal isolates representing 10 fungal species were obtained from wood samples and identified based on morphological characteristics and molecular methods: Cadophora novi-eboraci, Cadophora spadicis, Cryptovalsa ampelina, Diaporthe eres, Diplodia seriata, Dothiorella omnivora, Eutypa lata, Eutypella sp., Peroneutypa scoparia, and Phaeoacremonium sicilianum. Pathogenicity tests conducted under field conditions with all species using the mycelium-plug method indicated that Eutypa lata and Cadophora spp. were highly virulent to woody stems of walnut. This is the first study to detect and identify fungal trunk pathogens associated with diseased walnut trees in Europe.

Etiology of Branch Dieback and Shoot Blight of English Walnut Caused by Botryosphaeriaceae and Diaporthe Species in Southern Spain

English walnut (Juglans regia L.) is considered an economically important fruit crop worldwide. In Spain, little attention has been given to walnut diseases owing to the minor economic importance of the walnut crop in the country until recently. In 2017, typical symptoms of branch dieback and shoot blight of English walnut were observed in southern Spain. From 2017 to 2018, 10 commercial walnut orchards showing disease symptoms were surveyed. Botryosphaeriaceae and Diaporthe fungi were consistently isolated from affected shoots. Cytospora isolates were also recovered with minor relevance. Representative isolates of each fungal group were characterized based on colony and conidial morphology, optimum growth temperature, and comparison of DNA sequence data from the internal transcribed spacer, elongation factor 1-α, and β-tubulin genomic areas. Pathogenicity tests were performed on detached and attached shoots and on detached fruit by inoculating them with mycelial plugs. Botryosphaeriaceae and Diaporthe isolates had higher optimum growth temperatures (≈25 to 27°C) than Cytospora sp. (19.5°C). The following species were identified: Botryosphaeriaceae: Botryosphaeria dothidea, Diplodia seriata, Dothiorella sarmentorum, Dothiorella sp., Neofusicoccum mediterraneum, and N. parvum; Diaporthe: Diaporthe neotheicola, Dia. rhusicola, Diaporthe sp., and Phomopsis amygdali; and Cytospora sp. Botryosphaeriaceae isolates were the most aggressive fungi to walnut in all tissues evaluated, followed by Diaporthe isolates and Cytospora sp. N. parvum was the most virulent among the remaining species tested in any of the tissues evaluated, followed by B. dothidea or N. mediterraneum. This work is the first report to identify the fungal species causing this complex disease of English walnut in Spain and Europe.

Macrophomina Crown and Root Rot of Pistachio in California

In this study, declining pistachio rootstocks were detected in newly planted commercial pistachio orchards in Kern County, California. Symptoms were characterized by wilted foliage combined with crown rot in the rootstock. From diseased trees, 42 isolates were obtained, and all had similar cultural and morphological characteristics of Macrophomina phaseolina. Analyses of nucleotide sequences of three gene fragments, the internal transcribed spacer region (ITS1-5.8S-ITS2), partial sequences of β-tubulin, and translation elongation factor 1-α (TEF1) confirmed this identification, and 20 representative isolates are presented in the phylogenetic study. Testing of Koch's postulates showed that M. phaseolina, when inoculated to stems and roots of the pistachio rootstocks using mycelial plugs or a microsclerotial suspension, is indeed pathogenic to this host. The widely used clonal University of California Berkeley I (UCBI) rootstock appeared highly susceptible to M. phaseolina, suggesting that this pathogen is an emerging threat to the production of pistachio in California. This study confirmed the association of M. phaseolina with the decline of pistachio trees and represents the first description of this fungus as a crown rot-causing agent of pistachio in California.

Molecular Characterization of Diaporthe Species Associated With Hazelnut Defects

Fungi of the genus Diaporthe have been reported as the main causative agent of hazelnut defects in the Caucasus area. This study aimed to define which fungal species are present in defective hazelnuts grown in Turkey and confirm the role of Diaporthe spp. Seven hazelnut orchards were selected, with each one located in a different Turkish Province (Düzce, Giresun, Ordu, Samsun, Sakarya, Trabzon, and Zonguldak), and hazelnuts were collected at early and full ripening. Fungal isolation and identification were performed at the genus level based on morphological characteristics. Several genera were isolated, with Diaporthe spp. being among the prevalent. This was the only genus with increasing incidence from early to full ripening, and incidence at full ripening was positively correlated both with internal (ρ = 0.86) and visible defects (ρ = 0.81), which confirmed its role as the key causative agent of hazelnut defects. The correlation of defect occurrence with rainfall, reported in previous study, was not confirmed, possibly due to the low defect incidence. A total of 86 Diaporthe monosporic strains isolated from Turkish hazelnut samples, together with 33 strains collected in the Caucasus region and 6 from Italy, were analyzed with a multi-locus phylogeny based on three genomic loci (ITS, EF1-α, and tub). The results showed that Diaporthe strains can be grouped into 7 distinct clades, with a majority of Turkish strains (95%) being placed into a single clade related with D. eres. These samples were organized into several sub-clades, which indicates the existence of genetically diverse sub-populations.

Identity and pathogenicity of some fungi associated with hazelnut (Corylus avellana L.) trunk cankers in Oregon

Four fungi isolated from trunks and branches of European hazelnut (Corylus avellana L.) from commercial orchards in the Willamette Valley, Oregon were characterized and pathogenicity was tested on potted hazelnut trees. The acreage of hazelnuts in Oregon has expanded greatly in recent years in response to the availability of Eastern filbert blight resistant cultivars. Fungi were characterized using the BLASTn algorithm and the GenBank database with multiple partial gene sequence(s). If BLASTn and GenBank were not sufficient for species-level identification, then a multilocus sequence analysis (MLSA) was performed. The four pathogens were identified as Diplodia mutilla (Fr.) Mont., Dothiorella omnivora B.T. Linaldeddu, A. Deidda & B. Scanu, Valsa cf. eucalypti Cooke & Harkn., and Diaporthe eres Nitschke. All pathogens but D. omnivora have not been previously reported from European hazelnut in the literature. All four pathogens caused lesions on trunks bare root hazelnut trees cv. 'Jefferson' planted in pots in the greenhouse and fungi were re-isolated from inoculated trees. D. mutilla appeared particularly aggressive in repeated inoculation experiments.

Identification and Pathogenicity of Fungal Species Associated with Canker Diseases of Pistachio in California

A survey was conducted during 2015 and 2016 in pistachio orchards throughout the San Joaquin Valley of California to investigate the occurrence of canker diseases and identify the pathogens involved. Cankers and dieback symptoms were observed mainly in orchards aged >15 years. Symptoms of canker diseases included brown to dark brown discoloration of vascular tissues, wood necrosis, and branch dieback. In total, 58 fungal isolates were obtained from cankers and identified based on multilocus phylogenetic analyses (internal transcribed spacer, glyceraldehyde 3-phosphate dehydrogenase, β-tubulin, calmodulin, actin 1, and translation elongation factor 1α) representing 11 fungal species: Colletotrichum karstii, Cytospora californica, Cytospora joaquinensis, Cytospora parapistaciae, Cytospora pistaciae, Diaporthe ambigua, Didymella glomerata, Diplodia mutila, Neofusicoccum mediterraneum, Phaeoacremonium canadense, and Schizophyllum commune. Pathogenicity tests conducted in the main pistachio cultivars Kerman, Golden Hills, and Lost Hills using the mycelium-plug method indicated that all fungal species were pathogenic to Pistacia vera. All species tested caused cankers in pistachio branches, although virulence among species varied from high to moderate. Overall, N. mediterraneum and Cytospora spp. were the most widespread and virulent species associated with canker diseases of pistachio in California.

Understanding the Process of Latent Infection of Canker-Causing Pathogens in Stone Fruit and Nut Crops in California

The Botryosphaeriaceae family is considered a fungal family that includes pathogens causing latent infection of woody plants, and a number of species were identified as causal pathogens of canker and shoot blight diseases. To better understand the process of latent infection of major canker-causing pathogens in woody tissues in different tree crops important in California, shoot and bud samples were randomly collected from four tree crops: almond, dried plum, pistachio, and walnut. The previously developed DNA primers and quantitative real-time PCR (qPCR) assay systems were applied to detect six canker-causing pathogen groups, including Botryosphaeria dothidea, and species of Cytospora, Diplodia, Lasiodiplodia, Neofusicoccum, and Phomopsis. The concepts of molecular severity (MS) and latent infection index (LII) were introduced and applied to quantify the latent infection levels for these samples. Variation in incidence of latent infection among pathogen groups was observed, whereas the incidences were relatively low among species of Phomopsis and Diplodia. High incidences of Cytospora spp. were observed in two dried plum (prune) orchards. Most orchards showed high incidences of B. dothidea and Lasiodiplodia spp. and moderate incidences of Neofusicoccum spp. Variations in MS were observed among samples of the studied orchards, ranging from 4 to 8. The overall results of LII demonstrated that species of Diplodia and Phomopsis were less important in population development of canker-causing pathogens at the latent phase. Lasiodiplodia spp. were the most aggressive and had been well developed in populations among the studied tree crops. Cytospora spp. became predominant in two of the three dried plum orchards, whereas B. dothidea and Neofusicoccum spp. showed trends of increase in incidence across various tree crops. This study also demonstrated the usefulness of this sensitive qPCR approach in providing evidence of the latent phase of major canker-causing pathogens of stone fruit and nut crops at an early stage of latent infection in woody plant tissues.

Ecology and Epidemiology of Diseases of Nut Crops and Olives Caused by Botryosphaeriaceae Fungi in California and Spain

In recent decades, the cultivated area and production of nuts and olives have increased, driven by an increasing consumer interest in healthier food. Diseases of almond, pistachio, olive, and walnut crops caused by species belonging to the Botryosphaeriaceae family have caused concern worldwide. Although considerable progress has been made in elucidating the etiology of these diseases, scientific knowledge of other aspects of these diseases is more limited. In this article, we present an overview of the most important diseases caused by Botryosphaeriaceae fungi affecting almond, pistachio, olive, and walnut crops by focusing on ecology and epidemiology, primarily in California and Spain.

Interaction Between Diaporthe rhusicola and Neofusicoccum mediterraneum Causing Branch Dieback and Fruit Blight of English Walnut in California, and the Effect of Pruning Wounds on the Infection

Botryosphaeriaceae and Diaporthaceae species are the causal agents of branch dieback of English walnut in California. In this study, the effects of the interaction between Neofusicoccum mediterraneum and Diaporthe rhusicola were evaluated in vitro by using mycelial plugs or spore suspensions and in vivo by inoculating shoots and epicarps (hulls) of walnut. Single inoculations of each species and different coinfection treatments were performed under laboratory or field conditions. The influence of shoot age and susceptibility of bark or pith tissues to N. mediterraneum and D. rhusicola infection after pruning was also evaluated. In in vitro experiments, spore germination of D. rhusicola was significantly (P < 0.0001) reduced in the presence of N. mediterraneum spores. When D. rhusicola was inoculated at 4 days before N. mediterraneum, a delay in lesion development in shoots and hulls was observed compared with the other two interaction treatments. One- to 2-year-old shoots were more susceptible to infection and colonization by N. mediterraneum than 3- to 4-year-old shoots. In young shoots, inoculation in the pith tissue resulted in longer lesions than those observed on shoots inoculated in the bark. No significant differences were observed between the development of internal or external necrosis and the age of the shoots, or the susceptibility of bark and pith to D. rhusicola infection. This information is essential to better understanding the complex situation of this walnut disease toward developing control management strategies.

Phylogeny, Distribution, and Pathogenicity of Lasiodiplodia Species Associated With Cankers and Dieback Symptoms of Persian Lime in Mexico

Persian lime (Citrus latifolia Tan.) is an important and widely cultivated fruit crop in several regions of Mexico. In recent years, severe symptoms of gummosis, stem cankers, and dieback were detected in the Persian lime-producing region in the states of Veracruz and Puebla, Mexico. The aims of this study were to identify the species of Lasiodiplodia associated with these symptoms, determine the distribution of these species, and test their pathogenicity and virulence on Persian lime plants. In 2015, symptomatic samples were collected from 12 commercial Persian lime orchards, and 60 Lasiodiplodia isolates were obtained. Fungal identification of 32 representative isolates was performed using a phylogenetic analysis based on DNA sequence data of the internal transcribed spacer region and part of the translation elongation factor 1-α and β-tubulin genes. Sequence analyses were carried out using the Maximum Likelihood and Bayesian Inference methods. Six Lasiodiplodia species were identified as Lasiodiplodia pseudotheobromae, Lasiodiplodia theobromae, Lasiodiplodia brasiliense, Lasiodiplodia subglobosa, Lasiodiplodia citricola, and Lasiodiplodia iraniensis. All Lasiodiplodia species of this study are reported for the first time in association with Persian lime in Mexico and worldwide. L. pseudotheobromae (46.9% of isolates) was the most frequently isolated species followed by L. theobromae (28.1%) and L. brasiliense (12.5%). Pathogenicity on Persian lime young plants using a mycelial plug inoculation method showed that all identified Lasiodiplodia species were able to cause necrotic lesions and gummosis, but L. subglobosa, L. iraniensis, and L. pseudotheobromae were the most virulent.

Characterization and Pathogenicity of Botryosphaeriaceae Species Obtained from Avocado Trees with Branch Canker and Dieback and from Avocado Fruit with Stem End Rot in Chile

Several species of the Botryosphaeriaceae family have been associated with branch canker, dieback, and stem end rot in avocado (Persea americana Mill.). In Chile, the incidence of diseases affecting the avocado tree increased from 2011 to 2016, which coincided with a severe drought that affected avocado production. Moreover, distant countries importing avocados from Chile also reported an increase of stem end rot of ripe avocados. Therefore, the aims of this study were to identify the pathogen species associated with branch canker, dieback, and stem end rot of avocado in Chile and to study their pathogenicity. This study was conducted between 2015 and 2016 in 'Hass' avocado orchards located in the main avocado-producing regions in Chile. A diverse collection of fungal species was recovered from both necrotic woody tissue and necrotic tissue on harvested ripe fruit. On the basis of morphology and phylogenetic analyses of the internal transcribed spacer region (ITS1-5.8S-ITS2) and the translation elongation factor 1-α (TEF1-α) gene, eight species in the Botryosphaeriaceae family were identified: Diplodia mutila, D. pseudoseriata, D. seriata, Dothiorella iberica, Lasiodiplodia theobromae, Neofusicoccum australe, N. nonquaesitum, and N. parvum. For each of these species, pathogenicity studies were conducted on 1-year-old healthy Hass avocado plants. All isolates produced brown gum exudate and caused necrosis in the vascular system 3 weeks after inoculation. N. nonquaesitum, N. parvum, and D. pseudoseriata were the most virulent species. Necrotic lesions and cavities with white mycelia near the peduncle union were observed on Hass avocado fruit inoculated postharvest. L. theobromae, N. australe, and N. parvum were significantly more virulent than the other tested species in the Botryosphaeriaceae family. This study identified and characterized the pathogenicity of Botryosphaeriaceae species in Chile, which will prove useful to future research on these pathogens directed at establishing effective control strategies in avocado.