Evaluation of antisporulants for the control of Crinipellis perniciosa, causal agent of witches broom disease of cocoa. In: Agrotrópica v. 4 p. 7-15, 1992.

Abstract

The effectiveness of 12 systemic and six protectant fungicides to prevent sporulation of Crinipellis perniciosa, the causal agent of witches' broom disease of cocoa (Theobroma cacao), was assessed. The fungicides were applied to green brooms still attached to the trees and to dry detached brooms. These were subsequently kept in an environment conducive for sporulation. Production of basidiocarps on these brooms were monitored weekly for a total of 20 to 36 weeks. Tebuconazole and cyproconazole emerged as the most efficient antisporulants. Their effects were characterized by delay in the initiation of fructification, highly significant reduction in the percentage of active brooms and highly significant decrease in the number of basidiocarps produced per broom. Inoculum from basidiocarps formed on brooms sprayed with the chemicals were infective to cocoa seedlings. The results indicate that antisporulants could be used to reduce the inoculum intensity and consequently pod losses in regions with high witches' broom disease pressure.