Avoid sequential planting of whitefly-susceptible crops. Always separate successive plantings by sufficient time and space to avoid carryover of whiteflies and virus from crop to crop.
Associate susceptible and non-susceptible crops. Use attractive but tolerant crops such as squash or eggplant as traps to draw whiteflies away from less tolerant or virus-prone crops such as tomato.
Rotate susceptible and non-susceptible crops.
Associate susceptible crops with refuge crops capable of tolerating whitefly populations without spraying as a means of increasing numbers of beneficial insects.
Use biorational insecticides such as insecticidal soaps, oils, insect growth regulators to suppress whiteflies while preserving beneficial insects;
(1) The overall whitefly population begins with low numbers early in the season and increases as the season progresses unless reduced by unfavorable weather or breaks in the crop cycle. In south Florida whitefly numbers are lowest in the fall and highest in the spring. In south Texas populations are low in early spring, increase through the spring and summer and decline in the fall;
(2) Hot, dry weather favors rapid whitefly reproduction;
(3) A decline of host crop quality, such as after harvest, increases the likelihood that whiteflies will migrate to adjacent crops;
(4) Different crops and crop varieties can vary greatly in their susceptibility to whiteflies.
In Texas, early planting of susceptible spring crops and the use of short-season varieties will help crops escape the greatest whitefly pressure. Following cotton, whitefly numbers in fall vegetables begin high and eventually decrease with time, presumably because of the smaller acreage of available host crops, cooler weather and greater numbers of natural enemies in the fall. Therefore, delaying fall planting until the threat of heavy migrations has diminished can help to reduce whitefly problems.
In Florida, early planting of the fall crop is not encouraged because it shortens the summer fallow period. Temporal or spacial separation between fall and spring crops is helpful in reducing whitefly migration and primary inoculation of virus (tomato only) into the spring crop. Early crop destruction in the spring increases the summer fallow period, decreasing carryover of whiteflies and virus to the fall crop.
Working with these considerations in mind, a multi-tactic approach can be used to effectively manage whiteflies in agricultural situations.