Penicillium oxalicum Currie and Thom., an Entomogenous Fungus of the Rice Stem Borer Scirpophaga incertulas (Walker) (Pyraustidae: Lepidoptera)

During a survey conducted in the rice fields at Karamana, Trivandrum, egg masses of the rice stem borer Scirpophaga incertulas Walker were found to be infected by a fungus. The fungal pathogen was isolated in pure culture on potato dextrose agar and was identified as Penicillium oxalicum. The egg masses were sprayed with a spore suspension from five day old cultures containing 100 spores/ml and observed for two weeks. Twenty egg masses containing 30-50 eggs were used for the test. There was no emergence of larvae from treated egg masses whereas, 90% hatchability was observed in control. Mycelial growth was noticed within 48 to 72 h on the egg masses.