Patterns of diel flight activity of the greenhouse whitefly, Trialeurodes vaporariorum (Westwood), and sweetpotato whitefly, Bemisia tabaci (Gennadius), were investigated on poinsettia, Euphorbia pulcherrima Willd., and gerbera daisy, Gerbera jamesonii H. Bolus, under greenhouse and environmentally controlled conditions. Adult flight activity was monitored at 2-h intervals (from 0700 to 2100 h EST) at various heights using yellow sticky traps. Traps placed 5 cm above the top of the plant canopy caught more adults of both species than traps placed higher. The daily patterns of catches of T. vaporariorum and B. tabaci adults in the greenhouse were similar and were unimodal with peak catches occurring between 0900–1300 h. Numbers of adults caught on the sticky traps in the greenhouse were correlated with temperature and relative humidity for T. vaporariorum, but not for B. tabaci. Few adults were caught during the dark hours (from 2100 to 0700 h). Under constant temperatures of 20°, 25°, and 30°C, the flight activity patterns of both whitefly species were unimodal, with peak catches of T. vaporariorum and B. tabaci occurring in the morning and afternoon, respectively. Differences in temperature did not significantly alter the pattern of catches of adults on sticky traps. The lowest temperature for initiation of whitefly flight was 16–17°C for T. vaporariorum, and 17–18°C for B. tabaci.
Are Yellow Sticky Traps an Effective Method for Control of Sweetpotato Whitefly,Bemisia tabaci, in the Greenhouse or Field?