Effects of environment on the in vitro growth and development of Colletotrichum gloeosporioides isolates from the Philippines
Abstract
皇冠体育app environmental conditions that influence conidial germination, appressorium development and melanization, and appressorium germination in Colletotrichum gloeosporioides were investigated in vitro. 皇冠体育app effect of relative humidities (RHs) between 39鈥�100% and of temperatures of 20, 25 and 30掳C were determined. Results differed when two isolates of the anthracnose pathogen isolated from Philippine mangoes were compared. 皇冠体育app optimum temperature for production of appressoria by isolates I2 and I4 were 25 and 20掳C, respectively. Both isolates however had a similar temperature requirement (25掳C) for optimum cellulolytic activity. At 30掳C, more appressoria became melanized than at lower temperatures but frequency of penetration was highest at 25掳C. Under optimum conditions (25掳C, 100% RH) only 25% of appressoria produced infection hyphae on a cellulose membrane after 3 days incubation. 皇冠体育app effect of periods of low RH which preceded a 24 h period of high RH were also investigated. Conidia held at 63 and 86% RH for 1鈥�2 weeks retained viability, and still formed appressoria when placed at 100% RH. 皇冠体育app implication of these results in the use of a forecasting model developed previously are discussed.
Citation
Estrada, A.B.; Dodd, J.C.; Jeffries, P. Effects of environment on the in vitro growth and development of Colletotrichum gloeosporioides isolates from the Philippines. Acta Horticulturae (1993) 341: 360-370.