Diaporthe and Diplodia Species Associated with Walnut (Juglans regia L.) in Hungarian Orchards

Walnut (Juglans regia L.) production is a developing sector in Hungarian horticulture, where preharvest fruit rot increasingly causes economic losses. Previously, fungi from the Diaporthaceae and Botryosphaeriaceae families were isolated with high incidence rotten fruits. Here, we identify these pathogens different plant parts (twigs, buds, shoots) orchards north-east of Hungary, test their pathogenicity on immature nuts. Diaporthe eres Nitschke Diplodia seriata De Notaris identified isolates symptomatic asymptomatic based ITS (nuclear ribosomal internal transcribed spacer) tef1 (translation elongation factor EF-1-alpha gene) DNA sequences. Purified monocultures caused nuts following vitro inoculation. Our results suggest that D. lingering buds overwintering woody may affect seasonal through wound infection. Infection by species present parts, as well on/in has been reported Mediterranean countries. This first report such stepwise aetiology region continental weather. Climate change, associated weather patterns limitations fungicide use European Union, among other factors, could be responsible for increasing number infections damage pathogens.