Mark each infested plant so the population can be tracked and the effectiveness of insecticide applications can be checked. Yellow sticky cards continuously trap flying adults during times when they are active. These traps provide an accurate indication of pest presence and movement. However, they represent little more than a token effort, unless the cards are placed almost touching foliage, are changed according to a schedule, and data are recorded and used. Place at least one sticky card per 1,000 square feet or two in a small freestanding greenhouse.
Yellow cards are more attractive to whiteflies than blue cards.
Make counts of whitefly species and life-stages during scouting trips. Devise a location marking system so the cards can be taken down, replaced, and transported to a convenient location for closer scrutiny. Sticky cards should be replaced at least once per week. To check the effectiveness of pesticides, hang fresh cards after application and the insecticide reentry period has passed. Record Keeping Accurate records of whitefly species, life-stages, and locations, combined with careful study can help those involved in control decisions to identify infestation sources, susceptible cultivars, and insect population movements.