BIOLOGY OF FRUIT FLY, BACTROCERADORSALIS (HENDEL) ON SAPOTA

Studies on the biology of Bactrocera dorsalis on Sapota (cv. Kalipatti) indicated that the female laid eggs in small clusters just underneath the rind of fruit, 2 to 4 mm. deep in the epidermis. The average length and breadth of freshly laid eggs were 0.85 + 0.02 and 0.18 + 0.01 mm, respectively. An incubation period of eggs ranged from 2 to 4 days with an average of 2.86 + 0.83 days and hatchability was 81.06 + 8.92 per cent. The larvae passed through three instars. The neonate larvae were translucent and white with slight yellowish in colour except its mouth part, which was black green in colour. The total larval period was completed within 6 to 13 days. The pupation took place in the soil. The pupal period was of 7.86 + 1.33 days. The newly emerged, male and female adults of B. dorsalis were of faint brown to dark brown in colour. The wings of adults consisted of dark black spot on the apex part (apical angle). The average pre-oviposition, oviposition and post-oviposition period were 9.46 + 1.75, 5.8 + 1.49 and 3.7 + 0.98 days, respectively. The average fecundity of the female was recorded as 148.13 + 37.85 eggs. The average longevity of male was recorded as 11.46 + 1.94 days while, that of female was 18.96 + 2.29 days. Total life cycle completed in 24 to 33 days by male and 34 to 41 days by female.