Abstract
Three systemic fungicides, flutolanil, triadimenol and hexaconazole, were evaluated against witches’ broom disease of cocoa (Theobroma cacao L.) on young clonal plants and mature trees. Their effects on the growth of newly-formed cushion brooms and on basidiocarp production of dry brooms were also assessed. All formulations applied as pre-inoculation soil drenches to the young plants significantly reduced infection by Crinipellis perniciosa (Stahel) Singer. All fungicides also significantly suppressed further growth of the cushion brooms. Flutolanil and triadimenol reduced the numbers of basidiocarps formed on dry brooms. The results are discussed with suggestions for strategies for future investigations on chemical control of the pathogen.