Submitted to: Silverleaf Whitefly: 1997 Supplement to the Five Year National Research and
Publication Type: Abstract Only
Publication Acceptance Date: August 1, 1997
Publication Date: N/A
Two insect growth regulators (IGRS) that are selective against whiteflies became available for the first time in 1996 to Arizona cotton growers under emergency exemption. These IGRs were studied in a commercial-scale whitefly management trial in 1996. Ground and aerial applications were roughly equivalent over a wide range of variables examined. The rapid advance of the population resulted in the initial triggering of all thresholds within just 5 days. The control cost for the highest threshold was significantly less than for the middle threshold, but not for the lower threshold. Under emergency exemption, each IGR may be used only once per season. The sequence of use did not result in any consistent advantage in population suppression, cost, number of sprays needed, or yield. The IGR regimes were in general more efficacious, less disruptive, and less costly than the conventional insecticide regime. There were significantly fewer sprays needed by the IGR regimes compared to the conventional regime. All regimes successfully controlled whitefly populations for a 12 week period and cost significantly less than conventional programs tested in 1995. IGRs are effective, long-lasting, & less environmentally disruptive alternatives to conventional insecticides. They reduce the risk of secondary pest outbreaks and pest resistance, and increase the opportunity of natural enemy conservation.