The Asian Citrus Psyllid has been responsible for destroying thousands of acres of citrus in Florida with devastating results to the state's citrus growing counties.  The insect has spread to California and many Southern California counties have imposed full quarantines after the psyllid was found at several sites.  The threat to California's $2-billion citrus industry is serious.

Once a tree has been infected by the psyllid that carries and transfers the huanglongbing (HLB) bacteria to the tree there has been no alternative but to quarantine the infected area and destroy the tree.  To complicate the issue further, the disease can lie dormant and be difficult to detect as the infection spreads from tree to tree.

Efforts to control the psyllid through pesticides have been ineffective and while quarantines have helped raise awareness and slowed some of the spread, a viable weapon to combat this invasive pest has been unavailable until recently.

Mark Hoddle, director at the Center for Invasive Species Research at UC Riverside, has been experimenting with a tiny parasitic wasp, Tamarixia radiata, that feeds on and kills the psyllid.  After a series of tightly controlled and successful tests, the wasps have been released on infected sites and have been effective in reducing the psyllid population.  There is no danger to pets or humans and the release program has been approved by the Department of Agriculture.

Although the results are promising, it's still too early to know the magnitude of the wasp's potential to effectively address this problem and more years of data will be required to assess it.  On the bright side, the use of the Tamarixia radiata wasp does provide a line of defense against this threat to citrus trees in the state.

To learn more about this effort, please see the UC Riverside Newsroom article.