Biological control is a means of reducing populations of an unwanted pest, like the Asian citrus psyllid, by using another insect that is a natural predator or parasite. In Asia, where the psyllid originates, a tiny wasp called Tamarixia radiata naturally preys on the Asian citrus psyllid, which prevents psyllids from spreading unrestrained. Here in California, this form of biological control is a good supplemental tool for lowering populations of the Asian citrus psyllid, although it’s not a solution on its own.

Trained teams of entomologists are releasing Tamarixia onto citrus trees in some residential areas of Southern California at no cost to residents. The use of Tamarixia in California is a cooperative effort of the University of California, Riverside, Citrus Research Board, United States Department of Agriculture and California Department of Food and Agriculture. To see where Tamarixia have been released, visit this University of California website map and turn on the parasite layers: