EVALUATION OF CULTURAL CHARACTERISTICS AND PATHOGENICITY OF SOME ISOLATES OF METARHIZIUM ANISO PLIAE AGAINST TEAK DEFOLIATOR, HYELAEA PUERA CRAMER

Investigations were carried out on pathogenicity of five Metarhizium isolates purified from mycosed Hyblaea puera larvae collected from teak plantations and nurseries in South India. The isolates were tentatively designated as MAl, MA2, MA3, MA4 and MA5. Observations on the morphology of the isolates showed variation in colour, size and shape of conidia. The conidia of MA and MA2 were observed to be oval to spherical, MA3 and MA5 oval and MA4 spherical. The isolates produced pale to dark green coloured conidial mat on the agar plates. Size of conidia varied from 2.79 um- 8.44 um X 2.76 um-3.72 m. Colony growth and conidia production were better at 25°C in all the isolates. The thermal death point of spores in water was close to 50°C for 10 minutes. SDA+Yeast Extract and PDA-Yeast Extract favoured better germination compared to other media. All the five isolates were pathogenic to Hyblaea puera larvae and the isolates MA3 and MA4 were more virulent producing cumulative mortality above 71% in Hyblaea puera larvae.