Phomopsis Destructum on Psidium Guajava Fruits in India

Abstract

A serious fruit rot disease of Psidium guajava L. was noticed in the gardens of the University campus and in local orchards. The disease is prevalent and on an average about 60% of the fruits of a plant were found to be affected. The disease first appeared in December and rapidly spread during February and March. The infected fruits showed disease symptoms near the stalk. Under favorable environmental conditions, infection centers are numerous. Lesions are dark brown, at first small and increase in size to 2 cm diam (FIG. 1). The tissues soften and the entire fruit rots within 8-12 da. The rotted fruits fall from the parent plants causing a heavy loss in the yield of the crop. The causal fungus was isolated from diseased fruits of guava. This fungus grew and sporulated on potato dextrose agar. With the help of Dr. Punithalingam of Commonwealth Mycological Institute, Kew, England the fungus was identified as species of Phomopsis. At present, species of Phomopsis are identified on the basis of the host. According to the available literature no species of Phomopsis has been described from Psidium; thus the present isolate is described as new. The specific epithet refers to the annihilating nature of the fungus. Some healthy fruits of Psidium guajava were inoculated with the fungus by inoculum disc after pricking the fruit surface and also by spraying with a suspension of spores in sterile water. Seven da after inoculation, fruits incubated at 30 C showed brown spots. Symptoms of rotting also appeared after 4 da. From the inoculated fruit the same fungus was re-isolated. 1963. A redisposition o some fungi ascribed to the Hyaloscyphaceae. 1132