The latest Arizona Vegetable Integrated Pest Management Update from the University of Arizona (UA) Cooperative Extension in Yuma, Ariz. released June 28, 2011.

Bagrada bug impact on 2010 desert cole crops

By John Palumbo, UA Research Scientist and Extension Specialist

The Bagrada bug, Bagrada hilaris, was a major problem in desert cole crops last fall. Widespread infestations were reported throughout the desert growing area in September and October where stand losses and yield/quality reductions to broccoli, cauliflower, cabbage, and other Brassica crops were considered economically significant in some growing areas.

In an attempt to document the impact of these outbreaks on desert production, a survey of pest control advisers (PCAs) from Yuma and the Imperial Valley was recently conducted to estimate the severity of Bagrada bug infestations on direct-seeded and transplanted cole crops during 2010.

A summary of the survey results can be found at this link: Bagrada Bug Survey 2010.

In general, a large percentage (98.6 percent) of direct-seed cole crop acreage (e.g., broccoli) was treated for Bagrada infestations with insecticides compared to transplanted cole crops (e.g., cauliflower) where 86.6 percent of the acreage was reported treated.

Similarly, estimates showed that direct-seeded cole crops sustained greater stand losses and plant injury from Bagrada feeding than transplanted crops. When combined, the average estimated stand loss and plant injury caused by Bagrada bug exceeded 15 percent and 10 percent in direct-seeded and transplanted crops, respectively.

PCAs also provided information on insecticides that provided effective control through 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 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 in Yuma last year.

Contact Palumbo: (928) 928-782-3836 or jpalumbo@ag.arizona.edu.