Biological Control

The California Department of Food and Agriculture’s (CDFA) Citrus Pest and Disease Prevention Division (CPDPD) uses a range of integrated pest management strategies to combat invasive pests and diseases.

One key effort focuses on the fight against the Asian citrus psyllid (ACP), the invasive pest responsible for spreading Huanglongbing (HLB). To help control the dangerous pest, agricultural officials are getting help from Tamarixia radiata, a beneficial parasitic wasp that is a natural predator to ACP, and can help limit ACP populations.

Tamarixia are tiny, stingless wasps that feed and reproduce on ACP nymphs, stopping them from reaching adulthood and reproducing. Harmless to humans and pets, Tamarixia serve as a highly effective natural tool designed to reduce ACP populations and slow the spread of HLB, which has no cure.

Tamarixia are natural predators to the Asian citrus psyllid.
Photo credit: UC Riverside

Tamarixia are raised inside CDFA’s Biocontrol Facility.

Tamarixia are small, no larger than about 1 mm long, roughly the size of a grain of sand.
Photo credit: UC Riverside

Tamarixia radiata specifically target ACP, feeding on ACP nymphs by laying eggs underneath. When the egg hatches, the larva feed on the ACP nymph.
Photo credit: UC Riverside

Tamarixia are released by CDFA in residential areas where known ACP populations are present.

Since launching its biocontrol program in 2012 in partnership with the University of California (UC), Riverside, CPDPD has released more than 34 million Tamarixia across California. What started as a focused effort on residential citrus trees in Southern California, where ACP first became established, has since grown into a key part of CPDPD’s statewide pest management approach. Today, CPDPD’s biocontrol program leads all Tamarixia rearing, domestic and international releases, and collaborates with partners including UC Riverside; California Polytechnic State University, Pomona; the United States Department of Agriculture; and Canine Detection Services.

While biocontrol efforts can naturally reduce invasive pest populations throughout California, community support remains critical. To learn more, visit our Pest and Disease page to identify how you can protect your own backyard trees.