A model for estimating infection levels of anthracnose disease of mango

Abstract

SUMMARY Anthracnose disease of mango caused by Colletotrichum gloeosporioides var. minor , spreads by water‐borne conidia from vegetative parts of the tree to attack inflorescences and prevent fruit set. An analysis of data from laboratory studies demonstrated that infection by conidia during wet periods was related both to the temperature and to the duration of the wet period. A model was used to estimate infection levels of anthracnose disease in two mango orchards over three seasons. The number of infection periods recorded and the estimated percentage of conidia forming appressoria in these periods matched disease development during flush growth and flowering. In 1980, only two infection periods were detected during flowering in one of these orchards and blossom blight did not prevent fruit set. In 1981 and 1982 however, higher estimated levels of infection were recorded more frequently during the same time and severe blossom blight developed. A second orchard, situated in an area less favourable to disease, was also monitored during 1982. Nine infection periods were recorded during flowering in this orchard compared to 14 in the first. A moderate level of blossom blight developed in this orchard.