A novel, integrated method for management of witches' broom disease in Cacao in Bahia, Brazil

Abstract

A three-year field study was conducted in Bahia, Brazil to validate several strategies for management of witches' broom disease in cacao caused by Moniliophthora perniciosa. Treatments which were applied alone or in combination included applications of biological control fungus Trichoderma stromaticum, fungicide copper hydroxide and phytosanitary broom removal. When compared with untreated control treatments, higher pod yields and consistently lower pod losses were obtained by alternating fungicide with biocontrol application. Pod losses caused by witches' broom were also reduced by fungicide treatment or by phytosanitary broom removal when applied alone or in combination, however total pod production per tree was consistently low whenever broom removal was used as a management strategy. While application of biocontrol fungus alone was not able to reduce witches' broom on pods, it reduced vegetative broom formation and also increased the number of pod-forming flower cushions. The present study indicates that alternating fungicide copper hydroxide with biocontrol fungus T. stromaticum without expensive phytosanitary broom removal is not only a better disease management strategy in Bahia but also results in better yields and thereby better net economic returns.