Study of the biology of the pavement ant documented a strong preference for fresh corn meal relative to tobacco seed. In the early 1980's, the western flower thrips began to spread from the Pacific coast throughout the United States and Canada. It is now established in most commercial greenhouses worldwide. Thrips and the several viruses it transmits have an unusually extensive host range of over 500 plant species in over 50 families. Therefore, nearly all commercial floriculture and vegetable crops grown in greenhouses are affected.
Control requires more pesticide use than for any other greenhouse problem.
Knowledge of thrips flight rhythms and dispersal characteristics can improve the timing and placement of pesticides. Barriers and the manipulation of air circulation patterns can limit thrips dispersal into areas where susceptible varieties are located. New research is concerned with identifying or developing repellents for use on flowers to control thrips populations and minimize injury often caused by pesticides. Of special interest is the registration of a food-grade product that can control thrips by a single application to floors and benches immediately before crops are placed in a greenhouse. This research is supported in part by Flowers Canada, Ontario and by AAFC Matching Investment Incentive.