Disease Note.

Nectria haematococca as a Stem and Fruit Pathogen of Sweet Pepper in the Greenhouse. W. R. Jarvis, Ontario Ministry of Agriculture and Food, Research Station, Harrow, Ontario NOR 1G0. S. D. Barrie, Agriculture Canada, and S. K. Khosla, Ontario Ministry of Agriculture and Food, Research Station, Harrow, Ontario NOR 1G0. Plant Dis. 78:926. Accepted for publication 17 May 1994. Copyright 1994 The American Phytopathological Society. DOI: 10.1094/PD-78-0926A.

In 1990, an estimated 50% yield loss occurred in a 1-ha sweet pepper crop (Capsicum annuum L. “Cubico”) grown hydroponically in rock wool. In subsequent years, less severe symptoms were noted in other pepper crops. Dark brown, sunken lesions occurred at the base of the stem and at scars left by removal of basal leaves and axillary shoots. Infection also occurred when the periderm was split by emerging axillary shoots. Lesions often girdled the stems and killed the tops of the plants. Leaves were slightly mottled between the veins, and fruit on affected plants had fine, longitudinal, paler striations. Calyx lobes became brown and curled upwards. Fruit rotted from beneath the calyx and occasionally from the flower end. Seeds were discolored brown, and the fruit cavity often had whitish mycelium. Lesions often had superficial whitish mycelium, sporodochia of Fusarium solani (Mart.) Sacc, and perithecia of Nectria haematococca Berk. & Broome. Isolations from surface-sterilized lesions and superficial mycelium yielded cultures of F. solani, and almost all isolates developed perithecia of N. haematococca. Reinoculation of stems and of harvested fruit reproduced the symptoms, and the fungus was reisolated. Seed from affected fruit also yielded cultures of N. haematococca. This disease has not been previously reported in North America but is known in the Netherlands and England (1 and in Hungary (2).