FLIGHT BEHAVIOR OF THE GREENHOUSE-WHITEFLY, TRIALEURODES-VAPORARIORUM (WESTWOOD) (HOMOPTERA, ALEYRODIDAE), IN RELATION TO YELLOW STICKY TRAPS

The placement of yellow sticky traps in relation to greenhouse-grown tomato plants affected the number of greenhouse whiteflies captured on traps. Whiteflies were caught on traps close to the ground when the traps were 1.0 m or more from plants, and were caught on traps level with the point from which they started flight when the traps were 0.5 m from plants. Traps 1.0 m from plants primarily caught whiteflies less than 5 days old, and trap catches were not correlated with numbers on plants; traps 0.5 m from plants caught whiteflies of all ages, and trap catches were correlated with numbers on plants. These results suggest that under field conditions greenhouse whiteflies would behave much like other species of whitefly, and would tend to be caught on traps close to the ground. In greenhouses, monitoring traps should be placed close to and slightly below the tops of the plants. Trap counts could be treated as samples from individual plants and used to make an estimate of population size in the greenhouse. Traps placed further from the plants monitor flight activity only.