2010 was a year that many winter cole crop vegetable growers in the Desert Southwest would rather forget, thanks to the bagrada bug which attacked plant seedlings en masse.

Since then, research conducted at the University of Arizona and the University of California has led to a better understanding of the pest, its biology, and has helped reduce yield and income losses for growers. 

When the bagrada bug made its 2010 grand entrance, winter vegetable growers, pest control advisers, and entomologists were stunned.  

“The pest caught us blind. Suddenly the bagrada bug was everywhere in the desert,” says John Palumbo, University of Arizona (UA) Extension specialist and entomologist based at the Yuma Agricultural Center.

Palumbo’s phone lit up like a Christmas tree. He jumped in the truck and headed to the fields. The first time Palumbo saw an adult bagrada bug he thought it was a trash bug moving out of recently defoliated cotton.

Get the  latest agricultural news each day to your Inbox. Click here for the free Western Farm Press Daily e-mail newsletter.

That fall and winter, cole crop growers suffered an estimated 14-percent yield loss on average in direct-seeded broccoli, according to follow-up surveys Palumbo conducted with pest control advisers. The average maximum loss was 36 percent.

“Some growers disked their fields under,” Palumbo said.

Yield losses since then have averaged about 6 percent; still a significant financial loss for cole crop growers.

Fast forward to the present. Palumbo and the UA’s Ta-I Huang, along with researchers at the University of California, Riverside – including Darcy Reed, Tom Perring, Nilima Prabhaker-Castle, and Jocelyn Miller - have learned a great deal about the destructive pest, Bagrada hilaris.

The scientists have a better understanding of the insect’s biology; vital information to help develop effective management solutions.

Palumbo discussed the latest bagrada bug research findings during the 39th annual California Association of Pest Control Advisers Annual Conference and Agri-Expo held in Reno, Nev. in October.

Cole crops are members of the Brassica family which include cabbage, broccoli, cauliflower, and other vegetables. While many plants can serve as hosts for bagrada - including alfalfa, Sudangrass, and cotton - the pest prefers to chow down on cole crop seedlings – vulnerable transplants and young plants after seed emergence.