Jeon, H.Y., Kim, D.S., Cho, M.R., Chang, Y.D., & Yiem, M.S. 2003 Temperature-dependent development of Pseudococcus comstocki (Homoptera: Pseudococcidae) and its stage transition models.. Korean Journal of Applied Entomology 42(1): 43-51.

Notes: This study was carried out to develop the forecasting model of P. comstocki for spray timing. Field phenology and temperature-dependent development of P. comstocki were studied, and its stage transition models were developed. P. comstocki occurred three generations a year in Suwon. The 1st adults occurred during mid to late June, and the 2nd adults were abundant during mid to late August. The 3rd adults were observed after late October. The development times of each instar of P. comstocki decreased with increasing temperature up to 25 deg C, and thereafter the development times increased. The estimated low-threshold temperatures were 14.5, 8.4, 10.2, 11.8, and 10.1 deg C for eggs, 1st+2nd nymphs, 3rd nymphs, preoviposition, and 1st nymphs to preoviposition, respectively. The degree-days (thermal constants) for completion of each instar development were 105 DD for egg, 315 DD for 1st + 2nd nymph, 143 DD for 3rd nymph, 143 DD for preoviposition, and 599 DD for 1stnymph to preoviposition. The stage transition models of P. comstocki, which simulate the proportion of individuals shifted from a stage to the next stage, were constructed using the modified Sharpe and DeMichele model and the Weibull function. In field validation, degree-day models using mean-minus-base, sine wave, and rectangle method showed 2-3 d, 1-7 d, and 0-6 d deviation with actual data in predicting the peak oviposition time of the 1st and 2nd generation adults, respectively. The rate summation model, in which daily development rates estimated by biophysical model of Sharpe and DeMichele were accumulated, showed 1-2 d deviation with actual data at the same phenology predictions.