DEVELOPMENTAL TIME OF PARABEMISIA-MYRICAE (KUWANA) (HOM, ALEYRODIDAE)IN DIFFERENT SEASONS AND A DEGREE-DAY MODEL

Developmental time of the whitefly Parabemisia myricae was measured ou tdoors in full sunlight on potted = trees. Cohorts of whiteflies that were oviposited on 14 Dec 1982, 27 Jan 1983, 8 Apr 1983, 15 Jul 1983, and 9 Sep 1983 took 105, 88, 52, 40, and 32 days, respectively, for 50 % of the adult whiteflies to emerge. Another cohort of whiteflies als o oviposited on 9 Sep 1983 and reared on plants in a shaded location w ithin several meters of the concurrent cohort reared on plants in full sunlight developed 5 days faster (total 27 days) than their full-sunl ight counterparts. Eeg to 50 % adult emergence data for whiteflies rea red in full sunlight and previously published data were best fit by a degree day model using a 12.8-degrees-C lower developmental threshold, a 30.6-degrees-C upper threshold (vertical cutoff) and a thermal cons tant of 265 degree-days. Developmental times of whiteflies in full sun light predicted by the model were within 14 % of observed developmenta l times. However, the whiteflies reared in shade developed 26 % faster than the model predicted. The model needs to be verified in commercia lly grown citrus.