The Bagrada bug, Bagrada hilaris, first occurred on desert cole crops at damaging levels in the fall on 2010, and since that initial outbreak the invasive stinkbug has become a major pest of desert cole crops. In 2012, widespread infestations were reported throughout the desert growing area from September and into early November, comparable to the infestations growers experienced in 2010. Stand losses and yield/quality reductions to broccoli, cauliflower, cabbage and other Brassica crops were considered economically significant in some growing areas, albeit at lower levels than reported in 2010. Insecticide usage to control this pest remains high. In an attempt to document these impacts, we have surveyed produce growers and PCAs from Yuma, Imperial Valley and central Arizona on an annual basis since 2010 to estimate the intensity of chemical management and severity of Bagrada bug infestations on direct-seeded and transplanted cole crops. A summary of the survey results can be found in the following report: Impact of the Bagrada Bug on Desert Cole Crops from 2010 - 2012: A Survey of PCA and Growers. Based on PCA estimates from the surveys, Bagrada bugs have occurred on greater than 85% of the direct seeded and transplanted cole crop acreage over the past 3 seasons. Similarly, almost all of these infested acres were treated with insecticides to control the pest. Averaged across all years, PCAs / growers reported treating direct-seeded crops for Bagrada bugs on a higher percentage of acres than where they reported that Bagrada bugs were present. On average, about 78.5% of the acreage was chemigated 1.6 times, and about 88% of the reported acres were sprayed an average of 2.3 times in direct seeded-crops. When the number of chemigations and foliar sprays are combined over all three years, almost 4 insecticides applications were made to control this pest. Damage from Bagrada bug infestations at stand establishment in both direct-seeded and transplanted crops has decreased by more than 50% since the initial outbreaks in 2010, likely a result of PCA awareness of the pest’s damage potential and better timing and use of chemigation treatments and foliar spray applications, as well as proper selection of effective products. PCAs also provided information on insecticides that provided effective control through both chemigations and foliar sprays. In general, they reported that products that have contact activity (i.e., Pyrethroids, OP/Carbamates) appeared to provide the most effective control against Bagrada adults on both direct-seeded and transplanted cole crops. Overall, the results of the PCA survey are consistent with results obtained in research trials conducted at the Yuma Agricultural Center over the past three years.

Remember: “ When in Doubt…… Scout”

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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.