Influence of temperatures on Life Table of Brevicoryne brassicae Linn.

Influence of six sets of temperature viz; 10, 15, 20, 25 and 30°C on the life table of Brevicoryne brassicae was studied. The demographic parameters viz; Gross reproductive rate (GRR), Netreproductive rate (R€ É0+É), Innate capacity of increase (rm), Finite rate of increase (ë), and Weekly multiplication of population (s•^rm)w were 49, 25.54, 0.252, 1.284 and 5.753, respectively which was maximum when the insect was reared at 25°C while it was minimum of 46, 5.28, 0.082, 1.085 and 1.770, respectively reared at 15°C. At 20C, the gross reproductive rate, net reproductive rate, innate capacity of increase, finite rate of increase and weekly multiplication was 47.0, 16.45, 0.174, 1.19 and 3.379, respectively. The effect of temperature was also profound on the mean length of generation (Tc) of B. brassicae. The mean length of generation (Tc) and doubling time were longest at 15°C (20.29 & 8.45, respectively) in comparison to 25°C which was 12.85 and 2.75, respectively.