BIOLOGICAL ASPECTS AND LIFE TABLE PARAMETERS OF THE EGGPLANT STEM BORER, Euzophera osseatella Treit. (Lep.: Pyralidae)

Biological aspects and life table parameters of the eggplant stem borer, Euzophera osseatella Treit. (Lep.: Pyralidae) were studied under laboratory conditions at 27℃ and 65% R.H. The egg, larval and pupal stages of E. osseatella lasted 5.8, 33.2 and 12.9 days, respectively. The mortality percentage in the corresponding stages reached 14, 37 and 13%, respectively. The sex ratio in E. osseatella was in favour of females (1:1.1). The preoviposition, oviposition and postoviposition periods of the pest averaged 1.8, 3.1 and 1.2 days, respectively. The daily and total numbers of eggs/female of E. osseatella were 46.6 and 147.2, respectively. The male and female of the insect lived 4.4 and 6.2 days, respectively. The mean generation time (T) of E. osseatella averaged 54.22 days. The net reproductive rate (Ro), the intrinsic rate of increase (rm) and the finite rate of increase (exp.rm/ λ) in the pest were 28.09, 0.062 and 1.063, respectively. The generation doubling time (Dt) of E. osseatella reached 14.01 days. The fecundity curve (Mx) of E. osseatella showed three peaks of 14.14, 20.14 and 12.32 female progeny/female/day at the female age (X) of 50.5, 61.5 and 63.5 days, respectively. The survival curve (Lx) of the insect revealed that most death of females occurred after an extended oviposition period to compensate failure of most immature stages to reach maturity (64%).