B.argentifolii (=B. tabaci biotype B) originated from a stock culture reared on poinsettia that was initiated in 1989 at Cornell University. The colony was maintained on bean IPhaseolus vulgaris L(Fabaceae)l in a walk-in growth chamber at 20-24°C and a L14:D10 photoperiod for two years. Three natural enemies, A. swin- skii, D.catalinae, and E.formosa, were purchased from a commercial supplier(IPM Laboratories Inc. Locke, NY. USA) and stored at 10°C