Effects of regular applications of benomyl on the population of Colletotrichum in mango leaves

Abstract

Colletotrichum gloeosporioides var. minor was found to be the dominant pathogen inciting anthracnose of mango leaves. It was isolated from 46 to 94% of leaf lesions in unsprayed trees, while C. acutatum, which can also cause anthracnose symptoms, was only isolated from 0–28% of lesions. Regular applications of benomyl significantly reduced the population of C. gloeosporioides var. minor but did not eradicate it from diseased lesions. Although unaffected by benomyl, the population or disease incidence of C. acutatum did not increase in sprayed trees. C. acutatum is unable to compete against the rapid increase in benomyl tolerant saprophytes which colonise infection sites previously occupied by C. gloeosporioides var. minor.