A new wood decay of kiwifruit in Italy

A previously undescribed form of wood decay of kiwifruit (Actinidia delicio sa (A. Chev.) C. F. Liang et A. R. Ferguson) plants was observed in 8-10-ye ar-old Emilia Romagna orchards in northcentral Italy. Symptoms appear as un specific interveinal chlorosis of the leaf, which later may become necrotic resulting in premature leaf drop. Fruits never grow as large as on healthy plants nor do they reach full maturity. This foliage chlorosis occurred on current season's shoots developing from canes growing horizontally from th e cordon. Cross-sections of the wood show white rot areas surrounded by bro wn necrosis of hard consistency, preceding the white rot in the colonisatio n of the wood. Isolations from the zone of hard consistency onto Potato Dex trose Agar (PDA) medium yielded Phaeoacremonium aleophilum, P. inflatipes, P. chlamydosporum, P. rubrigenum, and to a lesser extent, Phialophora sp., whereas Phellinus conchatus was commonly isolated from white rot diseased t issue. Although pathogenicity studies on host plants are still being carrie d out, a strong similarity with esca disease of grapevine could clearly be noticed.