With cauliflower and cabbage now being transplanted it’s time to be on the look-out for the elusive bagrada bug. Eleven years ago, the invasive stinkbug invaded the desert southwest, causing significant economic damage to large acreages of Cole crops. But in the past 5-6 years bagrada populations have been relatively light in our experimental plots (see graph below) and found sporadically in commercial crops. Why the drastic reduction? Not certain, but likely a combination of good insect management and a little help from mother nature. However, for the second year in a row, we found an abundance of adults and nymphs colonizing mustard and other brassica plots this past spring. Thus, you shouldn’t count them out this season; a lot will depend on how well they survived the long summer, and if there are any hitchhikers on transplants. To date, I’ve had reports from 2 local PCAs who have found single Bagrada adults on early transplanted cauliflower. In addition, bagrada bugs have been reported on cabbage transplants in the Phoenix area. No feeding signs on leaves reported is a good sign that numbers are light and may have arrived with the transplants. Similarly, I had reports during July of PCAs picking up Bagrada adults while sweeping cotton. Again, be aware of your surroundings, especially if you have a brassica crop going in the ground next to a defoliated cotton field. Experience over the past eleven years has shown us that peak adult bagrada bug abundance in the desert generally occurs on direct-seeded and transplanted brassica crops in mid-September. These peak occurrences appear to coincide with the end of the monsoon season and the much-reduced humidity. However, it’s been difficult to observe this effect lately since there has been a trend of significantly lower bagrada bug abundance since 2014, and last season was one of the lightest bagrada populations since we started tracking them in 2010. So, what should a PCA expect for this season? We’re having an active monsoon so far, and the higher humidity could play to your advantage. We can’t say for sure when they will show up and in what numbers but keep your eyes open for adults on your earliest plantings. Here are a few management tips to consider. (1) When monitoring for bagrada bugs, PCAs should look mainly for fresh feeding signs on new plant tissue, and adults later in the day when they are most active. (2) Direct-seeded and transplanted crops are susceptible to bagrada bug infestations during stand establishment and up to the 6-leaf stage. After that, bagrada rarely cause damage to head forming brassicas (ie., broccoli, cabbage, cauliflower). Leafy brassicas like kale are much more susceptible to cosmetic damage throughout the season though. (3) We recommend that control be initiated immediately if you can readily find 5% or more of plants with fresh-feeding signs. This can include chemigation or aerial applications with pyrethroids. Contact insecticides such as pyrethroids, Lannate, and Lorsban should be used once stands are lined out. Once pipe is pulled and adults continue to migrate into fields, consider alternating to dinotefuran (e.g., Scorpion) sprays. (4) Also, growers who plant NipsIt broccoli seed (clothianidin treated) should begin to closely monitor for fresh feeding damage around 14 days after emergence. More information on bagrada bug management on fall brassica crops see: Bagrada Bug Management Tips-2021.