Captan, the active substance in Buvicid K 370 SE, is a contact fungicide that is not absorbed by the plant but remains on the leaf surface to exert its effect. When introduced to the cells of the pathogenic fungi, it is transformed into a poisonous chemical compound. It is a protective active substance, meaning that it protects the plant by preventing the development of infection. To achieve the desired efficacy, the protective film formed by the fungicide has to be in place before the
infection occurs. As a result, great care has to be given to ensuring perfect coverage when spraying the leaves, as the product can slow but not block any infections.