Avocado (Persea americana) represents an important emerging tropical crop in Italy, especially in the southern regions. In this study, young plants of avocado showing symptoms of stem and wood lesion, and dieback, were investigated. Isolations from symptomatic tissues consistently yielded colonies of Neopestalotiopsis-like species. The characterization of representative isolates was based on the observation of morphological characters, the effect of temperature on mycelial growth rate, and on the sequencing of three different gene regions, specifically ITS, TEF1, and TUB2. Phylogenetic analyses were conducted based on maximum parsimony and maximum likelihood approaches. The results showed the presence of two species, viz. Neopestalotiopsis rosae and N. siciliana, the latter of which is here described as a new species. Pathogenicity tests were conducted using the mycelial plug technique on young potted avocado trees for both Neopestalotiopsis species. The results showed that both species were pathogenic to avocado. This study represents the first report of these two species affecting avocado and results in the description of a new species within the genus Neopestalotiopsis. Based on phylogeny, Pestalotiopsis coffeae-arabicae is combined in Neopestalotiopsis.

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.

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.

Pistachio (Pistacia vera) is an important crop in Italy, traditionally cultivated in Sicily (southern Italy) for several decades now. In recent years, new orchards have been planted in new areas of the island. Field surveys conducted in 2019 revealed the presence of symptomatic trees showing shoot dieback, cankers, fruit spots, and leaf lesions. Isolations from symptomatic samples consistently yielded fungal species in the Botryosphaeriaceae family. Identification of collected isolates was conducted using morphological and molecular analyses. Morphological characterization was based on conidia measurements of representative isolates and also effects of temperatures on mycelial growth was evaluated. DNA data derived from sequencing the ITS, tef1-α, and tub2 gene regions were analyzed via phylogenetic analyses (maximum parsimony and maximum likelihood). Results of the analyses confirmed the identity of Botryosphaeria dothidea, Neofusicoccum hellenicum, and N. mediterraneum. Pathogenicity tests were conducted on detached twigs and in the fields both on shoots as well as on fruit clusters using the mycelial plug technique. The inoculation experiments revealed that among the Botryosphaeriaceae species identified in this study N. hellenicum (occasionally detected) and N. mediterraneum were the most aggressive based on lesion length on shoots and fruits. N. mediterraneum was the most widespread among the orchards while B. dothidea can be considered a minor pathogen involved in this complex disease of pistachio. Moreover, to our knowledge, this is the first report of N. hellenicum in Italy.

Many fungi belonging to Botryosphaeriaceae are well-known as causal agents of diseases in economically and ecologically important agricultural crops and forest trees. In Italy, the high diffusion of Botryosphaeriaceae infections observed over the last decade, has shown the importance of this group of fungi, which are becoming limiting factors for plant production in agricultural systems, nurseries and natural and urban landscapes. Global warming and stress factors such as occasional extreme climatic events can affect the susceptibility of host plants, as well as fungus behaviour, increasing the risk of future infections. Available reports of Botryosphaeriaceae in Italy have been examined, focusing on wood and fruit pathogens, resulting in a list of ten genera and 57 species. Diplodia is the most widespread genus in Italy with 76 records on 44 hosts, while at species level, Neofusicoccum parvum, Botryosphaeria dothidea and Diplodia seriata show the widest host ranges and many records. The ability of the pathogens to remain latent on asymptomatic plants, and uncontrolled trade of plant materials among countries, facilitate the dissemination and potential introduction of new Botryosphaeriaceae species. Preventive detection and adequate control strategies are always needed to limit the potential damage caused by Botryosphaeriaceae. This review had particular emphasis on host-pathogen associations, disease symptoms, geographic distribution, metabolite production, and accurate pathogen identification.