Two field experiments were conducted during 1996 and 1997 cotton seasons to evaluate the initial and bio-residual eficacy of a num­ber of chemicals including: pyripoxyfen ( a juvenil hormone mimic), prim-bet (a mixture of fenpropathrin / pyriproxyfan) and four plant - derived oils (cotton seed oil, sunflower oil, corn oil and linseed oil) against the adult and immature stages of whitefly Bemisia tabaci (Genn.). Among the more effective compounds, primbet was the only one that induced over 70% reduction in population of whitefly during a period .of two weeks. All the tested compounds had moderate to low effect as the in­dividuals of the pest after spray were capable to renew the infestation rapidly and caused serious damage to cotton plants.