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Biological Control: Tamarixia

The Asian Citrus Psyllid - Diaphorina Citri Kuwayama

When an insect like the Asian citrus psyllid is introduced into a new environment free of predators, it can become an unwanted pest. Introducing a natural predator to that environment a process called biocontrol can help reduce populations of the pest. Tamarixia:

  • Is a natural predator of the Asian citrus psyllid elsewhere in the world
  • Is harmless to humans, animals and other insects
  • Can help save your citrus trees

What is Tamarixia?

The Insect: Asian Citrus Psyllid
Photo courtesy of Center for Invasive Species Research.

A tiny, stingless wasp called Tamarixia radiata is a natural predator of the Asian citrus psyllid and can help lower populations of the pest, thereby protecting your citrus tree. This tiny wasp no bigger than the period at the end of this sentence is harmless to humans and pets, but it feeds on young Asian citrus psyllids preventing them from reaching adulthood.

Trained teams of researchers and entomologists are releasing Tamarixia onto citrus trees in some residential areas of Southern California and are monitoring its effectiveness. This activity has no cost to the homeowners.

One way owners of citrus trees can help improve the effectiveness of Tamarixia is by placing ant bait around citrus trees and keeping trees well pruned. Ants can interfere with beneficial insects like Tamarixia and actually protect harmful pests like the Asian citrus psyllid. Visit a local nursery or home and garden center to learn about ant bait that can help.

What is Biological Control?

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, stingless wasp called Tamarixia naturally preys on the Asian citrus psyllid, which prevents it from spreading unrestrained. Here in California backyards, this form of biological control is a great tool for lowering populations of the Asian citrus psyllid, although it’s not a solution on its own. Learn about other actions that help protect against the Asian citrus psyllid and what you can do to help.

The use of Tamarixia in California is a cooperative effort of the University of California, Citrus Research Board, United States Department of Agriculture and California Department of Food and Agriculture. Researchers are currently exploring the effectiveness of another beneficial insect called Diaphorencyrtus aligarhensis for controlling the Asian citrus psyllid. To learn more about biological control, visit some of the websites listed on the Other Resources page.

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