Science Alert
Journal of Entomology
  Year: 2009 | Volume: 6 | Issue: 2 | Page No.: 102-108
DOI: 10.3923/je.2009.102.108
Variation in Germination and Growth Rates of Two Isolates of Beauvaria bassiana (Balsamo) Vuillemin (Deuteromycota: Hyphomycetes at Different Temperatures and their Virulence to Callosobruchus maculatus (Fabricius) (Coleoptera: Bruchidae)
Adaku A. Lawrence and Ayub Khan

This study aims to determine the effect of temperature on conidial germination, colony radial growth and virulence of two isolates of Beauvaria bassiana (ARSEF-1186 and IMI-351833) to the cowpea weevil, Callosobruchus maculatus under controlled laboratory conditions. Isolates grown on Potato Dextrose Agar plates indicated that the rate of conidial germination was slower at 20 °C than at 25 and 30 °C and was expressed by the following 50% Germination Time (GT50) values: 17.23 ± 1.02 h for ARSEF-1186 and 16.46 ± 1.02 h for IMI-351833. The lowest GT50 value was estimated as 12.33 ± 1.02 h for IMI-351833 at 25 °C. ARSEF-1186 showed significantly faster colony radial growth rate (Kr) than IMI-351833 for all temperatures investigated. Bioassays using Cajanus cajan seeds dipped in conidial suspensions of both isolates indicated that the highest virulence gainst C. maculatus adults was observed with ARSEF-1186 at 30 °C. This isolate exhibited both the lowest LC50 (2.29x105 spores mL-1) and LT50 (4.17 days) values.
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16 March, 2009
Jeff Lord:
Beauveria is spelled incorrectly in this paper.