EPIDEMILOGICAL SURVEYS OF GNOMONIA LEPTOSTYLA IN JUGLANS REGIA HEDGEROW TRAINED ORCHARD

Walnut anthracnose epidemilogy and distribution was monitored in a Persian (English) walnut orchard hedgerow trained, located in the Mediterranean area. Leaves were collected every 15 days from the four cardinal points and at three heights of the canopy. The number of spots, lesion size, and the number of acervuli were considered. Primary lesions resulted generally distributed throughout the canopy. Thus, different sources of inoculum, other than overwintered fallen leaves, should be considered. Lesion number and size as well as the number of acervuli increased during summer. A dramatic increase of disease incidence, statistically significant, started to be evident from late August to the end of September. This disease peak could be related to the increasing number of leaflets bearing fertile acervuli which supply an enlarging inoculum foci for secondary infections, and to the progressive senescence of leaves. Leaf position in the canopy seems not important for disease severity. The smallest lesion size and the lowest number of acervuli were found on juvenile leaves.

IV International Walnut Symposium

A. Belisario, E. Forti, A.M. Cichello, A. Zoina, E. Barbieri, A. Valier

anthracnose, walnut disease, epidemiology

https://doi.org/10.17660/ActaHortic.2001.544.54