INFLUENCE OF TEMPERATURE ON DEVELOPMENT, FECUNDITY AND SURVIVAL OF THE CABBAGE MOTH MAMESTRA-BRASSICAE (L) (LEP, NOCTUIDAE) IN RELATION TO THE IMPROVEMENT OF FORECASTING AND CONTROL METHODS

Developmental time and survival of eggs, larvae, pupae and adult femal es of the cabbage moth, Mamestra brassicae (L.), were investigated at different temperatures within the range of 5-23 degrees C. In addition , the influence of temperature during the larval period on the weight of the succeeding pupae was studied, as well as the effect of temperat ure on fecundity of adult females. The lower developmental thresholds (T-b) and thermal requirement (DD) were established for all developmen tal stages and the larval instars using linear regression analysis. T- b and DD were 8.6 degrees C and 75 degree-days for eggs, 5.4 degrees C and 496 degree-days for the total larval period, 7.2 degrees C and 30 4 degree-days for pupae, and 5.0 degrees C and 56 degree-days for the preovipositional period, respectively. Pupal mortality was low at all temperatures. The survival of eggs and larvae was highest at 18 degree s C, whereas mortality was 100% at 8.5 degrees C. Larval mortality was highest in the first instar and decreased with increasing age. Pupae gained the highest weight when the larvae were reared at 18 degrees C, and the weight decreased with declining temperature. Temperature had no significant effect on total fecundity or fertility. Fecundity was b asically unimodal distributed at all temperatures. At low temperatures the egg laying period was markedly prolonged.