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Citrus fruit crops are important in many countries. Anthracnose, post bloom fruit drop, fruit stem-end rot, twig and branch dieback and gummosis, caused by Colletotrichum spp., are diseases that seriously threaten citrus production. Surveys of kumquat (Fortunella margarita) orchards were conducted in Eastern Sicily, Southern Italy, during 2022-23. Fungi isolated from twig and branch dieback of F. margarita were identified as Colletotrichum karsti through multi-locus (gapdh, tub2 and act) phylogeny. Pathogenicity and aggressiveness on detached apple fruit and kumquat plants were confirmed for a selection of representative isolates, although with different levels of disease incidence observed. This is the most comprehensive study on identification of C. karsti as the causal agent of twig and branch dieback of kumquat. [ABSTRACT FROM AUTHOR]

Summary: During the winter of 2022, camphor trees (Cinnamomum camphora L.) showing symptoms of canker, wood discoloration and twig dieback were detected in a nursery located in Catania province of eastern Sicily, Italy. Samples were brought to the laboratory, and isolations revealed the presence of Botryosphaeriaceae spp. in symptomatic wood tissues. Representative isolates were sub-cultured and identified by sequencing. Specifically, the three loci (ITS, tef-1α, and tub2) were amplified by conventional PCR and sequenced. Phylogenetic analysis using the Maximum parsimony approach revealed that nine isolates were strongly clustered within the clade of Neofusicoccum parvum and one isolate within the clade of N. luteum. Pathogenicity tests were conducted by inoculating stems of 1-year-old camphor trees with mycelial plugs of three representative isolates of N. luteum and N. parvum. Nine days after the inoculation, the camphor trees showed the same symptoms as those observed in the nursery. To the best of our knowledge, this is the first report worldwide of N. luteum and N. parvum causing disease in camphor tree. [ABSTRACT FROM AUTHOR]

A recent survey conducted in the historical botanical garden Villa Caronia, Sicily, identified the causal organisms of branch cankers and dieback on a mature Meryta denhamii. Laboratory isolations and sequencing of three loci, namely ITS, tef1-α, and tub2, showed the presence of two species belonging to Botryosphaeriaceae, including Neofusicoccum parvum and Neoscytalidium dimidiatum. Pathogenicity tests confirmed that these species are able to induce canker symptoms on this host. To our knowledge, this is the first report, worldwide, of N. parvum and Ne. dimidiatum causing branch canker and dieback on M. denhamii. [ABSTRACT FROM AUTHOR]

The almond (Prunus dulcis) constriction canker caused by Diaporthe amygdali is considered one of the most important diseases of this crop in the European continent, especially in the Mediterranean countries. Field surveys conducted in Sicily, Italy, revealed the occurrence of almond trees severely infected by the disease. Symptoms of twig canker, shoot blight and gummosis were widely distributed in almond orchards grown with both local and international cultivars. The highest disease incidence and severity (DI and DS) were observed in the orchards grown with 'Ferragnes', 'Supernova' and 'Tuono' cultivars, whereas those grown with local sicilian cultivars such as 'Pizzuta' and 'Romana' showed the lowest DI and DS. Laboratory isolations yielded a total of 58 Diaporthe-like isolates. Morphological observations and molecular analysis based on sequencing and phylogenetic analyses of ITS, tef1-α and tub2 gene regions of representative isolates identified the causal agent as D. amygdali. The effect of temperature (5, 10, 15, 20, 25, 30 and 35 °C) was evaluated on mycelial growth rate on PDA and on lesion development in inoculated detached shoots, with the isolates tested showing an optimum growth temperature around 25 and 20 °C, respectively. Pathogenicity tests were conducted by means on detached almond shoots and on potted almonds plants. Results showed that all the isolates were pathogenic in all tissues evaluated showing significant differences in aggressiveness among the isolates. According to our results, this is the most updated study of constriction canker in Italy, including a molecular characterization of D. amygdali, since its first identification in 1936. [ABSTRACT FROM AUTHOR]

Increased branch canker and dieback were observed in commercial avocado (Persea americana) orchards in Sicily, Italy. Surveys were conducted in 2021 and 2022 on 11 orchards to investigate etiology of the disease. Seventy-five plants from four orchards, showing branch canker and dieback, were sampled. Isolations from woody diseased tissues revealed the presence of fungi (Botryosphaeriaceae). Identification of the isolates was achieved by morphological and multi-loci phylogenetic analyses (Maximum Parsimony and Maximum Likelihood) of the ITS, tef1-α, and tub2 loci. Botryosphaeria dothidea, Lasiodiplodia citricola, Macrophomina phaseolina, Neofusicoccum cryptoaustrale, and Neofusicoccum luteum were identified. Representative isolates collected from the orchards, characterized based on the tub2 locus and identified as N. parvum, were excluded from this study, since this species has already been reported in our territory. Pathogenicity tests were conducted on potted, asymptomatic, 2-year-old avocado trees using mycelial plugs. These tests showed that all the Botryosphaeriaceae species characterized in this study were pathogenic to avocado. This is the first report of L. citricola, M. phaseolina and N. cryptoaustrale causing canker and dieback on avocado trees, and is the first record of these fungi causing branch disease on avocado in Italy. [ABSTRACT FROM AUTHOR]

Pistachio (Pistacia vera) is an important Mediterranean crop. In Italy, pistachio is cultivated in the southern regions, of which Sicily is the main production area. Recently, the phytopathological situation of this crop has started to be updated, and new diseases have been discovered, studied, and reported. Botryosphaeriaceae spp. and Leptosillia pistaciae are major canker/rot pathogens, and Cytospora pistaciae and Eutypa lata have been reported as minor canker pathogens. In this paper, we evaluated different biological control agents, belonging to Trichoderma asperellum, T. atroviride and T. harzianum, as well as some Bacillus amyloliquefaciens strains, against above-mentioned pathogens. Results of dual culture assays showed that all the biological products, both fungi and bacteria, were able to inhibit the mycelial growth of the pathogens in vitro. Experiments using detached twigs showed no effect of biocontrol agents in reducing infections, except for Neofusicoccum hellenicum treated with T. harzianum T22 and Leptosillia pistaciae treated with B. amyloliquefaciens D747. Results of detached fruit experiments showed an efficacy ranging from 32.5 to 66.9% of all the biological products in reducing the lesions caused by N. mediterraneum. This study provides basic information for future research on biological control of pistachio diseases and future prospects for search of more effective biological control agents for canker diseases than those studied here. [ABSTRACT FROM AUTHOR]

In recent years, the cultivation of tropical fruit crops has increased in the Mediterranean basin, especially in southern Italy. In surveys conducted from 2014 to 2019 woody canker and shoot blight were observed on mango plants (cvs. Kent, Keitt, Sensation, Osteen, and Kensington Pride) and litchi plants (cvs. Way Chee and Kwai Mai Pink) cultivated in Sicily. Botryosphaeriaceae and Diaporthaceae were consistently isolated from symptomatic samples. Morphological characterization and multi-locus phylogenies using three genomic loci (a portion of translation elongation factor 1-α gene, a portion of the β-tubulin gene, and an internal transcribed spacer) identified these fungi as Neofusicoccum parvum, Lasiodiplodia theobromae, Botryosphaeria dothidea, Diaporthe foeniculina, and Diaporthe baccae on mango and Diaporthe foeniculina and Diaporthe rudis on litchi. Pathogenicity tests on healthy mango (cv. Kensington Pride) and litchi (cv. Way Chee) plants demonstrated the pathogenicity of the isolates used in the study, and Koch's postulates were fulfilled for all pathogens. To our knowledge, this is the first report of L. theobromae, B. dothidea, and Diaporthe species on mango in Italy and the first report worldwide of woody canker and shoot blight caused by D. foeniculina and D. rudis on litchi plants. [ABSTRACT FROM AUTHOR]

Exotic ambrosia beetles are increasing in Europe due to global trade and global warming. Among these xylomycetophagous insects, Xylosandrus compactus (Eichhoff) (Coleoptera: Curculionidae) is a serious threat for several Mediterranean host plants. Carob trees growing in Sicily (Italy) have been extensively attacked by beetles leading to rapid tree decline. Although X. compactus has been found in Europe for several years, most aspects of its ecology are still unknown. We thus studied the population structure and dynamics of X. compactus, together with its twig size preference during a sampling of infested carob trees in south east Sicily. In addition, fungi associated with insects or galleries were isolated and characterized. The results showed that, in this newly-colonized environment and host plant, adult X. compactus overwinters inside twigs and starts to fly and reproduce in mid spring, completing five generations before overwintering in late fall. The mean diameter of carob twigs infested by the beetle varied significantly over the seasons, with the insect tending to infest larger twigs as season progresses. The mean number of adults/gallery was 19.21, ranging from 6 to 28. The minimum temperature significantly affected the overwintering adult mortality. Ambrosiella xylebori and Fusarium solani were the main symbionts associated with the pest in this study. Acremonium sp. was instead recorded for the first time in Europe inside X. compactus galleries. Several other fungi species were also found for the first time in association with X. compactus. Our findings provide useful insights into the sustainable management of this noxious pest. [ABSTRACT FROM AUTHOR]

During June 2018, several symptomatic fig (Ficus carica) cuttings, showing twig blight, subcortical discolouration and apical dieback were collected from a nursery in Catania province, Sicily (Italy). Isolations from diseased tissue consistently showed the presence of the same fungal colony. Morphology of the fungal isolates together with sequence data of the nuclear rDNA internal transcriber spacer (ITS) region, translation elongation factor 1-alpha (tef1) gene and partial beta-tubulin (tub2) gene of representatives isolates revealed the presence of the fungus Neofusicoccum parvum. Pathogenicity tests were conducted by inoculating fig cuttings with mycelial plugs. After 10 days, the inoculated plants developed cankers similar to those observed in the greenhouse and after 26 days all inoculated plants were dead. To the best of our knowledge, this is the first report worldwide of N. parvum causing disease on this host. [ABSTRACT FROM AUTHOR]

A new disease of fennel is described from Sicily (southern Italy). Surveys of the disease and sampling were conducted during spring 2017 and 2018 in Adrano and Bronte municipalities (Catania province) where this crop is widely cultivated. Isolations from the margin of symptomatic tissues resulted in fungal colonies with the same morphology. Pathogenicity tests with one isolate of the fungus on 6-month-old plants of fennel reproduced similar symptoms to those observed in nature. Inoculation experiments to assess the susceptibility of six different fennel cultivars to infection by the pathogen showed that the cultivars 'Narciso', 'Apollo', and 'Pompeo' were more susceptible than 'Aurelio', 'Archimede', and 'Pegaso'. Phylogenetic analyses based on a matrix of the internal transcribed spacer (ITS), the large subunit (LSU), and the small subunit (SSU) rDNA regions revealed that the isolates represent a new genus and species within the Leptosphaeriaceae, which is here described as Ochraceocephala foeniculi gen. et sp. nov. This study improves the understanding of this new fennel disease, but further studies are needed for planning effective disease management strategies. According to the results of the phylogenetic analyses, Subplenodomus iridicola is transferred to the genus Alloleptosphaeria and Acicuseptoria rumicis to Paraleptosphaeria. [ABSTRACT FROM AUTHOR]

During the winter of 2017, dieback and canker symptoms were observed on pistachio (Pistacia vera) in two orchards in the Bronte area, Catania Province, Sicily, Southern Italy. Two different fungi were consistently isolated from infected tissues. Morphological observations and multi-locus phylogenies using five genomic loci (ITS, act, rpb2, tef1 and tub2) identified these fungi as Cytospora pistaciae and Eutypa lata. Pathogenicity tests on 5-y-old potted plants of P. vera grafted on terebinth (P. terebinthus) reproduced similar symptoms as those observed in nature, and Koch's postulates were fulfilled for these two pathogens. This study is the first to report dieback and canker diseases of pistachio caused by C. pistaciae and E. lata in Italy. [ABSTRACT FROM AUTHOR]

During 2009–2013, 302 single-spore isolates of Botrytis cinerea were collected from vineyards located in the most important site of table grape production in Sicily, recognized by the European Community as Protected Geographical Indication (PGI) ‘Mazzarrone grape’. In preliminary studies, all isolates were tested in vitro for their sensitivity to six fungicides belonging to the following groups: benzimidazoles, dicarboximides, anilinopyrimidines, succinate dehydrogenase inhibitors, hydroxyanilides and phenylpyrroles. In these tests, 45.7% of the isolates were found to be resistant to at least one fungicide. Specific resistance to pyrimethanil was found in 30.8% of the isolates, whereas 13.9, 10.3 and 7.6% of the isolates exhibited resistance to carbendazim, iprodione and boscalid, respectively. No isolates resistant to fenhexamid and fludioxonil were detected within our dataset of B. cinerea isolates. However, 30 B. cinerea isolates possessed multiple resistance to two or more fungicides. In detail, 8 isolates were simultaneously resistant to four fungicides, whereas 5 and 17 isolates were resistant to three and two fungicides, respectively. For boscalid, 11/23 of isolates showing in vitro resistance possessed a mutation at the Sdh B gene, whereas all isolates resistant to carbendazim and iprodione possessed mutations at β-tubulin and BcOS1 histidine kinase genes, respectively. Accordingly, these fungicides failed to control gray mould infections caused by resistant or reduced sensitivity isolates on grape berries and grapevine leaves whereas the sensitive isolates were effectively managed by all fungicides applied at label rates. This study represents the first report of B. cinerea field isolates resistant and/or with simultaneous resistance to several botryticides from table grape vineyards in Sicily. Therefore, current strategies for fungicide resistance management of B. cinerea could be negatively affected in future. [ABSTRACT FROM AUTHOR]

Passion fruit (Passiflora edulis Sims.) is an ever-increasing interest crop in Italy because it is mainly cultivated for its edible fruit and, secondly, as an ornamental evergreen climber. During the summer of 2020, two-year-old plants of purple passion fruit in one of the most important expanding production areas of Sicily (southern Italy) showed symptoms of yellowing, wilting, and vascular discoloration. Fusarium-like fungal colonies were consistently yielded from symptomatic crown and stem tissues. Five representative isolates were characterized by a morphological and molecular analysis based on a multilocus phylogeny using RNA polymerase's second largest subunit (RPB2) and translation elongation factor 1-alpha (EF-1α) genes, as Fusarium nirenbergiae (Fusarium oxysporum species complex). Pathogenicity tests conducted on healthy 1-year-old passion fruit cuttings revealed symptoms similar to those observed in the field. To our knowledge, this is the first report of Fusarium wilt on passion fruit caused by Fusarium nirenbergiae. This report focuses on the phytopathological implications of this fungal pathogen, which may represent a future significant threat for the expanding passion fruit production in Italy and Europe. [ABSTRACT FROM AUTHOR]

Key lime (Citrus aurantiifolia) is an emerging crop in Italy, especially in the Southern regions, where the environmental conditions are suitable for its cultivation. A field survey in Sicily in a commercial orchard of Key lime revealed the widespread presence of water-soaked spots and sunken/dry lesions at the stylar-end, mainly in pre-harvest condition. Water-soaked spots were attributed to Geotrichum citri-aurantii, an agent of sour rot on Citrus spp., whereas the sunken/dry lesion was attributed to the physiological disorder known as stylar-end breakdown. Sour rot and stylar-end breakdown are usually considered post-harvest diseases and rarely found in the field on fruit still attached to the tree. Although Geotrichum citri-aurantii is not responsible for the stylar-end breakdown, its association with this alteration reveals the importance of the environmental conditions and the agronomic practices in diseases/disorders development. In addition, to our knowledge, this is the first report of Geotrichum citri-aurantii on Key lime in Europe. [ABSTRACT FROM AUTHOR]