IDENTIFICATION OF VIRULENT ISOLATE OF METARHIZIUM ANISOPLIAE (METSCHIN) SOROKIN (DEUTEROMYCOTINA: HYPHOMYCETES) FOR THE MANAGEMENT OF HELICOVERPA ARMIGERA (HUBNER)

ABSTRACT Conidia of the entomopathogenic fungi Metarhizium anisopliae (SBT # 27 and SBT # 28) were produced under standard condition and then examined for influences on vitro conidial germination speed and virulence to an insect host, Helicoverpa armigera. Conidia were most virulent (based on mortality at 6 d) and had the fastest germination rates when produced on SMB (Sabouraud maltose broth) and the media pH is 6.0 - 6.2. The second instar larvae were exposed to the fungus and the concentration is of 1 x 107 and 1 x108 conidia/ml were tested against host insects at 280 C, SBT # 27 isolates showing 98 - 100% mortality in 8days against H. armigera and SBT # 28 showing 90 - 92% in 8 days. Among the two isolates SBT # 27 is superior in terms of high percent kill as well as 100% germination of conidia within 48 hours. However, SBT # 27 isolate showing greater pathogenicity against insect pest.