The almost microscopic, oblong, pale green to purple eggs are inserted into the lower leaf surface, often in a circle or crescent. Biology Greenhouse whiteflies are worldwide pests of greenhouse-grown ornamentals and vegetables. First discovered in England in 1856, they were found in the United States in 1870. Tropical Central or South America are suggested origins of the greenhouse whitefly. Greenhouse whiteflies infest a wide variety of ornamental and vegetable crops, and they can survive outdoors during the growing season, particularly in sheltered locations.
Infested plants become chlorotic and unthrifty.
Secondary infections of honeydew and sooty mold further detract from the appearance of the crop. Unless controlled, greenhouse whiteflies may completely destroy the commercial value of a floricultural crop. Adults are usually found on the lower surface of new leaves. Here they insert their eggs that hatch 5 to 7 days later. The new crawlers move about the plant for a day or two, often from leaf to leaf before inserting their mouthparts to feed.