PATHOGENICITY OF BEAUVERIA BASSIANA (DEUTEROMYCOTA: HYPHOMYCETES) AGAINST THE YELLOW RICE STEM BORER, SCIRPOPHAGA INCERTULAS (LEPIDOPTERA: PYRALIDAE) UNDER LABORATORY CONDITIONS

Two isolates (274 and 373 ) with concentrations ranging from 10^5 to 10^9 spores ml^-1 of the entomopathogenic fungus Beauveria bassiana (Bal.) Vuill were evaluated for pothogenicity against immature stages of yellow rice stem borer, Scirpophaga incertulas (Walker) under laboratory conditions at Rice Research Institute, Dokri, Sindh Pakistan. Not only the highest rates of mortality of S. incertulas were recorded at higher concentrations of spores, ml^-1 but also reduced percentage egg hatching of yellow rice stem borer. Log dose (spores/ml) of the fungus B. bassiana isolate No. 274 and isolate No.373 on egg, larva and pupa of S. incertulas was recorded as 5.12, 5.46, 6.10 and 6.23, 8.33, 8.33, respectively. The isolate No.274 was more pathogenic than the isolate No.373 to control of S. incertulas.