Abstract
The control effect of Penicillium waksmanii Zaleski (T-141), which was isolated from mango leaves and showed the strongest antagonistic effect against Colletotrichum gloeosporioides in vitro was tested on the mango fruits and leaves in the laboratory. There was no effect when both T-141 and C. gloeosporioides were inoculated on the mango fruits and leaves, simultaneously. However, when T-141 was pre-inoculated three days before C. gloeosporioides, the percentage of disease severity decreased to less than 50% after 7 days. Although the latent period was longer for the leaves than for the fruits, the anthracnose symptoms were recognized at 20 days after inoculation at the rate of 100% for only C. gloeosporioides, and at the rate of 60% for the simultaneous inoculations. Compared to the pre-inoculation with T-141, the incidence decreased to 40% and the severity index decreased to 10%. It is assumed that C. gloeosporioides is widely distributed on mango fruits and on leaves, because the anthracnose symptoms were recognized when distilled water was sprayed on the surfaces, while no symptoms were observed with only T-141. A chloroform fraction extracted from a cultured broth of T-141 displayed an antifungal activity to C. gloeosporioides. T-141 also inhibited the germination, germ tube development and appressorium formation. C. gloeosporioides was sensitive to several fungicides such as benomyl and thiophanate-methyl, unlike T-141. Moreover, both fungi grew well at 25-30°C. These findings suggest that single application and use of a combination of fungicides may exert on inhibitory action against anthracnose and its progression.
