title: Environmental and Pathogenic Factors Inducing Brown Apical Necrosis on Fruit of English (Persian) Walnut.
abstract: Brown apical necrosis (BAN) is a most recently described disease affecting English (Persian) walnut fruit. BAN was only recorded in intensively managed walnut orchards and was found to be a disease complex mainly caused by Fusarium species. All fungi associated with this disease are polyphagous and ubiquitous, not specific to walnut. Consequently, BAN occurrence is more strictly dependent, than generally, on the interaction between pathological features and environmental conditions. Environmental variables identified with regression analysis showed that maximum temperature, angle of main wind direction versus tree row orientation, and orchard distance to the closest river/canal, all representative of climatic conditions occurring in the orchard, were related to fruit drop. The factor displaying the highest influence on severity of BAN fruit drop was maximum temperature and only subordinately factors are associated with relative humidity. BAN symptoms were reproduced with in planta artificial inoculation, and fruit drop of symptomatic fruit was significantly higher than that of the noninoculated trees for each type of inoculum (Fusarium semitectum, F. graminearum, and Alternaria spp.). F. semitectum and F. graminearum were more aggressive than Alternaria species, and the earliest artificial inoculations in mid-May resulted in the highest fruit drop. The extension of walnut fruit susceptibility and the conducive environmental factors to BAN are discussed.
authors.affiliation: First author: Department of Agronomy Foods Natural Resources Animals and Environment, University of Padova, Viale dell'Università 16, 35020 Legnaro, Padova; second author: Nogalba, Consorzio Produttori di Noce, 45010 Pettorazza, Rovigo, Italy; third author: Il Noceto, Società Consortile s.r.l., 31040 Chiarano, Treviso, Italy; and fourth author: Consiglio per la Ricerca in Agricoltura e l'analisi dell'economia agraria-Centro di Ricerca per la Patologia Vegetale (CRA-PAV), Via C. G. Bertero 22, 00156 Roma, Italy.
authors.forename: Michele
authors.initials: M
authors.lastname: Scotton
authors.affiliation: First author: Department of Agronomy Foods Natural Resources Animals and Environment, University of Padova, Viale dell'Università 16, 35020 Legnaro, Padova; second author: Nogalba, Consorzio Produttori di Noce, 45010 Pettorazza, Rovigo, Italy; third author: Il Noceto, Società Consortile s.r.l., 31040 Chiarano, Treviso, Italy; and fourth author: Consiglio per la Ricerca in Agricoltura e l'analisi dell'economia agraria-Centro di Ricerca per la Patologia Vegetale (CRA-PAV), Via C. G. Bertero 22, 00156 Roma, Italy.
authors.forename: Enrico
authors.initials: E
authors.lastname: Bortolin
authors.affiliation: First author: Department of Agronomy Foods Natural Resources Animals and Environment, University of Padova, Viale dell'Università 16, 35020 Legnaro, Padova; second author: Nogalba, Consorzio Produttori di Noce, 45010 Pettorazza, Rovigo, Italy; third author: Il Noceto, Società Consortile s.r.l., 31040 Chiarano, Treviso, Italy; and fourth author: Consiglio per la Ricerca in Agricoltura e l'analisi dell'economia agraria-Centro di Ricerca per la Patologia Vegetale (CRA-PAV), Via C. G. Bertero 22, 00156 Roma, Italy.
authors.forename: Antonio
authors.initials: A
authors.lastname: Fiorin
authors.affiliation: First author: Department of Agronomy Foods Natural Resources Animals and Environment, University of Padova, Viale dell'Università 16, 35020 Legnaro, Padova; second author: Nogalba, Consorzio Produttori di Noce, 45010 Pettorazza, Rovigo, Italy; third author: Il Noceto, Società Consortile s.r.l., 31040 Chiarano, Treviso, Italy; and fourth author: Consiglio per la Ricerca in Agricoltura e l'analisi dell'economia agraria-Centro di Ricerca per la Patologia Vegetale (CRA-PAV), Via C. G. Bertero 22, 00156 Roma, Italy.
authors.forename: Alessandra
authors.initials: A
authors.lastname: Belisario
mesh_terms: D004777:Environment; D005638:Fruit / Q000382:microbiology; D005670:Fusarium / Q000502:physiology*; D054884:Host-Pathogen Interactions; D031324:Juglans / Q000382:microbiology*; D010935:Plant Diseases