Pathogenicity of fungi associated with leaf spots of kiwifruit

Fungi commonly isolated from necrotic lesions on leaves, flowers, and fruit of kiwifruit (Actinidia deliciosa (Chevalier) Liang et Ferguson; syn. A. chinensis Planchon var. hispida Liang) were tested for their ability to infect artificially wounded and unwounded leaves on 4-5-month-old seedlings of kiwifruit cv. Hayward. Eight fungi were tested: Alternaria alternata (Fr.) Keissler, Botryosphaeria parva Pennycook & Samuels, Colletotrichum acutatum Simmonds, Cryptosporiopsis sp., Fusarium acuminatum Ellis & Everhart, Glomerella cingulata (Stonem.) Spauld. et von Schrenk, Phoma exigua Desm., and Phomopsis sp. All fungi were capable of invading wounded tissue but rarely caused lesions spreading from the wound site. Unwounded leaves were rarely invaded by any of the fungi. Old leaves were more readily invaded by fungi than young leaves. The fungi tested are best viewed as wound parasites capable of colonising injured host tissue but not able to directly attack healthy tissue.