The Asian citrus psyllid (ACP) is expanding northward from Southern California, raising the threat of huanglongbing disease. Work at several of UC ANR's Research and Extension Centers has been preparing by looking at various ways to control the insect, since there is no cure for this deadly disease of citrus.

Hansen REC funded a project to look at a natural enemy of the ACP, a parasitoid wasp from Pakistan. After extensive trials the Tamarixia wasp has been released in more than 400 different areas in Riverside, San Diego, San Bernardino, Orange, Imperial and Los Angeles counties. So far, results are promising, with the apparently successful predators being recovered as far away as 5-8 miles from their release site.

The wasp is one tool in the Integrated Pest Management kit; it is not the silver bullet solution. Entomologist Mark Hoddle and his team are hoping for a 30% parasitism rate year-round (the wasp is more able to find prey during the summer months). For every psyllid larva the wasp kills, it is one less ACP for the growers to worry about, and the wasps are out there working 24/7/365 for free. At this early stage most of the activity is happening in urban areas. As improved control strategies are developed, biocontrol may have a positive role to play in commercial conventional orchards.