The adult whitefly emerges from the pupal case and flies to other host plants to lay eggs and begin the cycle again. Fourth instar nymphs (called pupae) and adults are most frequently used to distinguish one species from another. With these crops, it is necessary to control whiteflies prior to the formation of this canopy or to space plants.
Whiteflies ("whitefly" or "white fly") are common pests of indoor crops, greenhouses and tomatoes. Seasonal pests in most outdoor areas, whiteflies can be found year-round in southern states or enclosed growing areas (greenhouses, hoop houses, grow tents). Their rapid reproduction rate makes them difficult to control once established.
Whitefly Control. To prevent Whitefly infestation: Whitefly infestations can expand very rapidly, so preventative treatments are a great way to go. You can do preventative treatments in winter or cold months of the year with a garden oil to smother and eliminate overwintering whiteflies and their eggs. Cotton Whitefly Control Knack® Insect Growth Regulator is a highly selective, long-lasting foliar treatment to control whiteflies in cotton. Dependable, long lasting tool for early protection. Adult whitefly image courtesy of Scott Bauer, USDA Agricultural Research Service, rapidshoot.info