In two forest plots, competing trees were killed or cut around stump sprouts of American chestnut trees. Chestnut blight cankers were treated with hypovirulent (dsRNA-containing) strains at least once a year for 4 years to control the blight disease. Nine years after the first treatment, abnormal cankers were found as far as 75 and 55 meters from the edges of the treatment areas, and strains isolated from these cankers contained dsRNA molecules. The dsRNA was found in strains with vegetative compatibility types different from those of the treatment strains, indicating that dsRNA had spread to other strains and had been maintained in the pathogen population. Trees in areas with abnormal cankers had more live stems per sprout clump and more cankers per live stem than trees in a comparison area with a similar harvest history, and more than trees in an undisturbed forest area. For. Sci. 36(1):113-124.
Document Type: Journal Article
Plant Pathology and Ecology, The Connecticut Agricultural Experiment Station, Box 1106, New Haven, CT 06504