GERMINATION, RADIAL GROWTH AND VIRULENCE OF METARHIZIUM ANISOPLIAE AND PAECILOMYCES FUMOSO-ROSEUS ON BEMISIA TABACI GENNADIUS (HOMOPTERA: ALEYRODIDAE)

The effect of temperature on germination, radial growth and virulence of Paecilomyces fumoso-roseus and Metarhizium anisopliae isolates on the sweet potato whitefly, Bemisia tabaci Genn., was studied in the laboratory. Time for fifty percent conidial germination (GT50) was significantly different among the isolates with optimum temperature for germination being 30°C. Colony radial growth rate Kr (8m h^-1) determined by linear regression analysis was fastest for isolate 9-91M (Kr = 68.89 8m h^-1) at 25°C. Lowest LC50 (1.46 x 10^3 spores ml^-1) for B. tabaci was for isolate 9-91M at 20°C while the lowest LT50 (0.9991 days) was recorded for isolate 11-91P at 25°C. Isolates 11-91P and 9-91M performed the best and we conclude that these isolates have good potential for the management of B. tabaci in the field.