Allow 48 hours between using these products and applying any fungicides in the greenhouse since this will destroy the active fungal spores in the insecticide. By killing off the whiteflies natural enemies or introduced biological controls, segments of the surviving whitefly populations are left unchecked and can easily become out of control. Whiteflies are usually kept in check with natural predators and introduced biological controls. Whiteflies are noted for gaining insecticide resistance easily. IPM of Alaska has documented pesticide resistant whiteflies throughout the greenhouse industry in Alaska.
Whiteflies can develop pesticide resistance easily.
Pesticide resistance is nearly always present in some degree in whitefly populations in Alaska greenhouses. Pesticide resistant strains of aphids are created through the use of insecticides. The more insecticide applied, the greater the selection for resistance. Never increase dosages. For example, by killing off susceptible whiteflies, there remains an untouched resistant whitefly that becomes a larger segment of the remaining population.