Bagrada Bug Management on Desert Cole Crops (September 17, 2014)

With fall produce now underway bagrada bugs have begun to show up on direct seeded and transplanted cole crops. Reports of bagrada in local cole crops are beginning to trickle in from PCAs and so far, the pressure does not appear to be as heavy as we’ve seen in the past few years. Populations of bagrada bugs at the Yuma Ag Center however, are as heavy as ever and are quickly causing damage to untreated broccoli plots. Based on research conducted over the past four growing seasons, peak abundance of bagrada bug has occurred from late September to early October. So, what should a PCA expect for this season? Can’t say for sure, but don’t be complacent just because you’re not finding a lot of bagrada adults on your first few fields. 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 susceptible to bagrada bug infestations during stand establishment and up to the 6 leaf stage. Furthermore, results suggests that it doesn’t take a large number of bagrada adults to cause significant stand losses or crop injury. In untreated plots, we have consistently observed significant damage (15-20% blind plants) to direct seeded plants during the first 7 days after emergence (cotyledon to 1-leaf Stage) with only finding an average of 1 bagrada adult / 6 row ft. If you readily find fresh feeding signs and/or adults during stand establishment, control should be initiated immediately. 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 and pipe is pulled. After stands are established and plant size increases up to the 2 leaf stage, or on tagged transplants, consider alternating to dinotefuron (Venom/Scorpion) to protect 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”