With the fall produce season quickly approaching, now is a good time to begin thinking about Bagrada bugs. It has been four years since this invasive species first showed up in the desert, but it has clearly found a home on local cole crops. The graph below shows Bagrada bug abundance on untreated broccoli and cabbage plantings at the Yuma Ag Center over the past three years. Last year populations were higher during the fall than we’ve seen to date. Over the course of the summer, there have been reports of adults found in alfalfa seed, sudangrass and weeds, and Bagrada were found in the Yuma Valley as recently as this week on broccoli seedlings. So, what should a PCA expect for this season? Don’t know for sure, but do not become complacent just because you’re not finding any Bagrada on your first sets. It would be wise to assume they will eventually show up in some intensity in some of your acreage, and you should prepare for them accordingly. Monitoring for Bagrada at stand establishment should focus on fresh feeding signs on new plant tissue, and adults later in the day when they are most active. Research and anecdotal observations in fields conducted over the past 2 years suggests that direct-seeded and transplanted crops are most susceptible to Bagrada bug infestations during stand establishment (cotyledon to 4-leaf stage). Furthermore, results suggest that it doesn’t take a large number of Bagrada adults to cause significant stand losses, and/or crop injury. If you readily find fresh feeding signs and /or adults in young stands control should be initiated. This can include chemigation with pyrethroids, and using contact insecticides (pyrethroids, Lannate, Lorsban) once stands are lined out and pipe is pulled. After stands are established and plant size increases up to the 1-2 leaf stage, or on tagged transplants, consider alternating to dinotefuron (Venom/Scorpion) for protecting plants from Bagrada feeding. This neonicotinoid will also provide knockdown of adult whiteflies and nymphs. More information on Bagrada bug management on fall cole crops can be found in these Veg Update briefs: Bagrada Bug Management Tips for the Low Desert and Knockdown and Residual Control of Bagrada Bug with Foliar Insecticides in Broccoli: 2013 Efficacy Report.

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.