Reducing Sprays in Areas, and Border Nets

By Jessica Theisman, Associate Editor

Entomologist Beth Grafton-Cardwell

Huanglongbing, vectored by the Asian Citrus Psyllid, (ACP) is the dreaded disease that has nearly wiped out the Florida citrus industry and is a potential problem for citrus growers in California. California Ag Today recently met with Beth Grafton-Cardwell, a UC Cooperative Extension Specialist. She specializes in integrated pest management; she discussed new strategies for the control of HLB.

“We have been surveying grower orchards in southern California and following how pesticide sprays are working, and I’m going to make some new recommendations on how to handle the populations down there,” said Grafton-Cardwell, who is also the director of the Lindcove Research and Extension Center. “Some regions of Southern California are easier to control psyllids than others. The pesticide treatment is less intensive due to the desert climate. San Diego is one of the areas that is less intensive due to the drier trees making them more hardened off, with less new flushes, where ACP is attracted.”

“There are other areas of southern California where the trees flush continually, providing great places for the psyllids to lay eggs, and that is where treatments are going to have to intensify,” she explained.

Areas such as Ventura, Riverside, and San Bernardino have to increase their treatments in the fall for better control.

And researchers are currently studying new prevention and control methods.

“Texas A & M has been looking at erecting net-like borders around the orchards because the psyllid tends to go to the edges,” Grafton-Cardwell said.

They want to treat the netting with yellow strips of sticky paper that would attract and/or apply insecticides to kill the psyllid.

“Our research is showing that often the infestation starts on the borders. Growers may have to intensify the number of treatments, but they don’t have to treat the entire orchard,” Grafton-Cardwell said. “Growers might be able to fight the psyllid with only treating the trees on the outer edges.”