I think we can finally conclude that Bagrada bugs have found a home in the desert southwest. Beginning in mid-April, PCAs began reporting the presence of Bagrada bugs on Brassica weeds, seed crops, and canola. By early May, they could easily be found reproducing in these crops throughout the Yuma area. Now, adults are being found fairly regularly in cotton. Numerous PCA's have reported picking up adults in sweep net samples, generally 1-2 per 50 sweeps with counts as high as 30 adults per 50 sweeps. We previously speculated that cotton in the Yuma area may serve as a bridge to fall produce crops, however we are uncertain whether Bagrada bugs can (a) reproduce on cotton during the summer, and (b) cause feeding damage to squares and small bolls similar to other stinkbugs. Studies are presently underway in the laboratory and field to address these questions. To date, we have found that field-collected adults caged on cotton seedlings can live as long as 40 days, but they don't appear to be reproducing.

There have been other reports out of Imperial Valley of Bagrada bug adults on Bermuda grass and alfalfa seed crops. Adults have been swept from forage alfalfa in the Yuma Valley. There is also a report from Coachella Valley that Bagrada bugs were observed damaging peppers. However, the most alarming observation thus far has been in the Imperial Valley. Last week I observed extremely high numbers of adults and nymphs feeding on a variety of plants including lemon trees, Russian thistle and other unknown desert plants (see pictures). Presumably these populations had developed during the spring on weeds (mustards) that were clearly abundant in the surrounding desert. For a list of known host plants, and an updated list of crops and plants where Bagrada bugs have been found throughout the desert southwest, 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.