Results from the recent Lettuce Insect Losses Workshop reveal some interesting trends in insecticide usage on Arizona head lettuce. Data were summarized from PCA and grower surveys completed over the past 6 years. When compared by class of chemistry using the IRAC mode of action classification system, the pyrethroids have consistently been the most commonly used insecticide class by far. Over the past few years their usage has declined only slightly. In contrast, the next most commonly used class, the spinosyns (Radiant and Success), was used on about half as many acres in 2010 and down significantly since 2005. This is likely due in part to the recent registration of the diamides (Coragen, Voliam Xpress) which were treated on significant acreage in both 2009 and 2010. Due to regulatory issues, Ketoenol usage (Movento) was down significantly in 2010 (~ 3 fold reduction) and was compensated by a large increase in neonicotinoid usage. Overall organophosphate/ carbamate/ endosulfan usage has steadily decreased in the past few years due to regulatory issues and the availability of the new reduced risk products. To view the insecticide usage data for 2005-2010 go to this link.

To contact John Palumbo go to: jpalumbo@ag.arizona.edu

For questions or comments on any of the topics please contact Marco Pena at the Yuma Agricultural Center.
College of Agriculture, The University of Arizona, Tucson, AZ.