RNGR.net is sponsored by the USDA Forest Service and Southern Regional Extension Forestry and is a colloborative effort between these two agencies.

U.S. Department of Agriculture USDA Forest Service Southern Regional Extension Forestry Southern Regional Extension Forestry

Skip to content. | Skip to navigation

Home → Publications → American Chestnut Proceedings → 1982 → Endothia Parasitica on Nuts of Castanea Dentata

Endothia Parasitica on Nuts of Castanea Dentata

ABSTRACT.--The chestnut blight fungus was reported on nuts of Castanea sativa in Pennsylvania in 1915. Visual examination of germinating American chestnuts in the spring of 1981 indicated that 38 percent, 88 of 234, were infected with Endothia parasitica. These were collected from trees at Lockwood Experimental Farm, Hamden, in an area where cytoplasmic hypovirulent strains have been introduced. Our initial identification wased on the presence of orange mycelial fans just below the epidermis of the nut shell and on fruiting pustules that erupted through the shell. Apparent E. parasitica was isolated free of contaminants from 26 of 41 infected nutstested. Fourteen of these isolates displayed varying degrees of abnormal morphology in culture. Two of the isolates are hypovirulent based on apathogenicity test on American chestnut. Several isolates are being tested for double-stranded RNA. Infection of the nut shell does not appear to affect germination or health and vigor of seedlings through the first growing season. The means by which these nuts become infected and possible significance for spread of hypovirulent strains is being examined.


Download this file:

PDF document Download this file — PDF document, 172Kb

Details

Author(s): Nancy K. DePalma, Richard A. Jaynes

Publication: American Chestnut Proceedings - 1982