Effect of temperature on biology of Brevicoryne brassicae L. and Myzus persicae Sulzer of cabbage

Knowing the effect of temperatures on growth and development of crop pests is essential. In this study, effect of six temperature regimes on the cabbage aphids Brevicoryne brassicae L., and Myzus persicae Sulzer was studied in Manipur, India. For both the species, 25˚C was found to be the optimal in relation to the most of the parameters studied; B. brassicae could not tolerate the extreme temperatures and died in its 2nd nymphal stage. A decrease in reproductive periods with increase in temperature may accommodate 1-2 additional brood(s) a year, consequently will lead to increased damage to cabbage, more particularly, under staggered transplanting.