With brassica crops now being established it is important to be on the look-out for the elusive bagrada bug. The invasive stinkbug invaded the desert southwest 14 years ago and caused significant economic damage to large acreages of Cole crops.  But in the past several seasons bagrada populations have been relatively light in our experimental plots and only found sporadically in commercial crops. Last fall, they were not very abundant and only reported in localized areas requiring minimal control. Why the drastic reduction?  We’re not certain, but likely a combination of good insect management in nurseries, preventative control in  and the field, and a little help from mother nature.  However, we did find an a few adults and nymphs colonizing brassica plots late last spring. Thus, you shouldn’t count them completely out this season; a lot will depend on how well they survived the long hot summer, and if there are any hitchhikers on transplants.  To date, I’ve had two reports of a couple of adults found on early transplants.  But you never know, bagrada have been known to survive the summers on cotton, alfalfa, Bermuda grass, Sudan grass, citrus, and weeds. So, be aware of your surroundings, especially if you have a brassica crop going in the ground next to one of these alternate host crops.  Experience over the past years has shown us that peak adult bagrada bug abundance in the desert generally occurs on direct-seeded and transplanted brassica crops in mid-late September.   These peak occurrences appear to coincide with the end of the monsoon season; cooler mornings and much-reduced humidity.  However, it has been difficult to observe this effect lately since there has been a trend of significantly lower bagrada bug abundance since 2014.  
 
So, what should a PCA expect for this season?   We’re not having much of a monsoon so far, and the lower humidity could play to the bagrada bugs advantage. We can’t say for sure when they will show up and in what numbers but keep your eyes open for adults and their feeding damage on your earliest plantings.  Here are a few management tips to consider. 

• When scouting 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.  
• 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 collards and kale are much more susceptible to cosmetic damage throughout the season though.  
• We recommend that control be initiated immediately if 5% or more of plants have fresh-feeding signs. This can include chemigation or aerial applications with pyrethroids. Contact insecticides should be used until stands are lined out.  Once pipe is pulled and adults continue to migrate into fields, consider alternating to neonicotinoid (e.g., Venom, Scorpion, Endigo) sprays.  These sprays will also help with whiteflies. 
• Also, growers who plant NipsIt broccoli seed (clothianidin treated) should begin to closely monitor for fresh feeding damage around 14 days after cotyledon emergence.  

 
**** For more information on bagrada bug management on fall brassica crops go to this link:     Bagrada Bug Management Tips-2024.