Effect of temperature on biology and population growth parameters of Aphis gossypii Glover (Hom., Aphididae) on greenhouse cucumber

Temperature-dependent development, survivorship and reproduction of the cotton aphid, Aphis gossypii on Cucumis sativus L. were evaluated at six constant temperatures (10, 15, 20, 25, 30 and 35 degrees C). Developmental periods of immature stages varied from 20.70 days at 10 degrees C to 3.81 days at 30 degrees C. The population failed to survive at 35 degrees C. As temperature increased, the intrinsic rate of increase (r(m)) followed a typical asymmetrical dome-shape pattern, with maximum value of 0.419/day at 25 degrees C. Survival of immature stages differed from 55.97% to 93.14% within the range of 10-30 degrees C. The average adult longevity ranged from 8.56 days at 30 degrees C to 17.00 days at 25 degrees C. Three mathematical models were compared for accuracy in predicting the developmental rate of A. gossypii, and estimating its temperature thresholds and optima. The developmental threshold was estimated to be 6.19 degrees C, and the thermal constant was 97.09 degree-days, using the linear model. The Briere 2 and Lactin 2 models were accepted for success to satisfy criteria of goodness-of-fit (residual sum of square and coefficient of determination) and estimable temperature threshold parameters and highly recommended for the description of temperature-dependent development of A. gossypii. No other data are available in using nonlinear models to describe the relationship between temperature and A. gossypii development.