Abstract

In a survey carried out in Kerala during 1986-88, microbial pathogens assiciated with the pests of two forest tree species, teak (Tectona grandis) and ailanthus (Ailanthus triphysa) were recorded and studied. A virus disease was recorded on the teak defoliator, Hyblaea puera and subsequent pathogenicity trials indicated that the virus is pathogenic even at a lower concentration of 10 x square of ten PIB/ml killing about 40 percent of the test larvae. It required about three days for the larva to die after infection with the virus. A fungal infection of H. puera caused by Hirsutella sp was recorded in a single instance. The bacterial pathogens recorded include, Enterobacter aerogenes, Bacillus thuringiensis H.l. var. thuringiensis and Bacillus cereus, Pseudomonas aeruginosa, Serratia narcescens. In the inoculation experiments, B. thuringiensis caused 100 percent mortality of the test larvae by 72 hours after infection. Paceilomyces farinosus and P. fumasoroseus were the