Control of cashew black mould by acibenzolar-S-methyl

Abstract

Black mould is one of the most important foliar diseases of dwarf cashew plants in coastal zone of northeastern Brazil. In order to develop a reliable method to control this disease, a feld experiment was conducted in the 2008/2009 season to evaluate the effect of acibenzolar-S-methyl (ASM) on disease severity at three different intervals with two, four and six times of applications per season. Copper oxychloride was used every 15 days as a control fungicide. An adult cashew orchard of the susceptible clonal variety CP-76 was used. Black mould severity was estimated by monthly evaluations by scoring each plant according to a 0 to 4 severity scale. Disease severity indexes per plot and per month were used for statistical analyses to compare treatment effects. ASM signifcantly reduced black mould in the epidemic season tested. Two applications of ASM at 30 days interval were enough to reduce disease in cashew plants. © Brazilian Phytopathological Society.