What is in this article?:
- Bagrada bug reappears in desert cole crops
- Bagrada bug control
- The California and Arizona cole crop industries are all abuzz about the repeat appearance of the Bagrada bug, Bagrada hilaris, in low desert fields this fall in Southern California and Arizona.
- Bagrada bug was first found in the United States in 2008 in Los Angeles County and then spread to neighboring Orange County.
- Bagrada bug attacks conventionally- and organically-grown cole crops.
Bagrada bug control
For Bagrada bug control, Palumbo suggests pyrethroids in chemigation for a cost effective, quick knockdown, but foliar applications are the most effective. For aerial applications on larger plants, products including neonicotinoids and Lorsban offer good control.
“There is a lot to learn about the Bagrada bug,” Palumbo said. “It’s a brand new pest and it may take several years for us to figure out how to best manage the insect.”
Palumbo expects the pest to be less of a concern by November when temperatures cool off.
Eric Natwick, entomology farm advisor, University of California Cooperative Extension, Imperial County, Holtville, concurred that Bagrada bug numbers about doubled this fall in the county compared to last year.
“We’re finding high concentrations of the Bagrada bug,” Natwick said. “Even though we can spray and can kill the insect, large numbers are found again several days later.”
He found Bagrada bugs during the spring and summer months in canola, alfalfa, and cotton.
“We know it survives through the summer on weeds and some crop hosts even though it doesn’t necessarily cause damage to the plants,” Natwick said.
Cole crop nurserymen in September reported Bagrada bugs inside greenhouses.
“They treated them and then several days later had more Bagrada bugs in the greenhouse,” Natwick said. “I suggested soil treatments under the benches where the transplants are grown.”
Finding high Bagrada bug numbers this fall means the insect survived the spring and summer and more.
“We are generating our own Bagrada bugs now where last year we thought they came into the valley from the mountain areas to the west,” Natwick said.
Stink bugs are more active at night due to cooler temperatures. During the day the insects stay mostly in the soil or in dirt clod shadows to escape the heat.
Growing cole crops under row covers is an option to protect plants from the Bagrada bug, but is an expensive option, Natwick says.