EFFECT OF LOW TEMPERATURE STORAGE ON THE FECUNDITY AND PARASITIZING EFFICACY OF BRACON HEBETOR (SAY)

Abstract

These studies were conducted in the Department of Entomology. University of Agriculture, Faisalabad during 2002. Effect of cold storage periods {1, 2. 3 and 4 weeks) at varying temperatures (5. 10 and 20°C) on late pupal stage of the larval parasitoid Bracon hebetor (Say) was studied to measure mean number of adults emergence, sex ratio, longevity of adults, number of larvae developed per one female and number of parasitized larvae of host per female. The results showed that there was negative relationship between number of emerged adults (females and males) and storage period for each tested temperature. The results further showed that sex ratios for males were more than the female for all tested temperatures and within all the periods. On the other hand longevity of the adults (females) was reduced due 10 low temperature for all the tested periods. [t ranged from 23.94-6.81, 23.22 - 9.06, 21.05- 14.57 and 21.14 days at § to 20°C for all periods, respectively. For males it ranged from 13.36 - 2.88, 15.86 ~ 4.86, 13.32-10.70 and 14.40 days on the same temperatures and storage periods, respectively. A negative relationship was observed between the number of larvae that developed from the emerged adults after storage as well as for the number of parasitized larvae of host for all storage periods. These ranged from 76.94 ~ 47.25, 72.5-53.07. 65.38-54.63 and 61.80 larvae at 5 to 20°C for | to 4 weeks and 43.05-19.06, 62.06 - 21.09, 66.77- 48.08 and 70.7 parasitized larvae on 5 to 20°C for all storage periods, respectively.