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Insect Warfare: A Timely Holiday Gift for Citrus Growers


Insect Warfare: A Timely Holiday Gift for Citrus Growers

UC Riverside entomologists to release natural enemy of Asian citrus psyllid, Dec. 20

(December 15, 2011)

A female <i>Tamarixia radiata</i>. The tiny parasitic wasp lays eggs in Asian citrus psyllid nymphs, eventually killing them.  Photo credit: Mike Lewis, CISR, UC Riverside.  (More images, including a map of the biocontrol grove, below.)Enlarge

A female Tamarixia radiata. The tiny parasitic wasp lays eggs in Asian citrus psyllid nymphs, eventually killing them. Photo credit: Mike Lewis, CISR, UC Riverside. (More images, including a map of the biocontrol grove, below.)

MEDIA ADVISORY

WHAT: UCR entomologists will release Tamarixia radiata, a tiny parasitic wasp that lays eggs in Asian citrus psyllid (ACP) nymphs. The larvae eat the ACP nymphs, killing them, and emerge as adults about 12 days later. Adult female Tamarixia also eat other ACP nymphs, thus killing them.

Reporters will have the opportunity to speak with the entomologists about the ACP, its economic impact, and how the release of Tamarixia – the first time in California – can help shrink the ACP population.

The adult ACP is 1/8th of an inch long; Tamarixia is about 1/16th of an inch long. Photographers and videographers are advised, therefore, to bring appropriate camera lenses.

UCR’s Center for Invasive Species Research (CISR) has high resolution photographs of ACP and Tamarixia for print and web publication.

WHEN: 11 a.m., Tuesday, Dec. 20. Media representatives may arrive as early as 10:30 a.m.

WHERE: In a 7.5-acre biocontrol grove of citrus trees near the UCR Botanic Gardens. Proceed toward the Botanic Gardens and follow signs to the biocontrol grove and the location of the Tamarixia release. Parking is available near the entrance to the grove.

WHO: UCR Executive Vice Chancellor Dallas Rabenstein and Mark Hoddle, the director of the CISR, will release the parasitic wasps (a total of 100-200 males and females). Representatives from the Citrus Research Board and the California Department of Food and Agriculture also will be present.

BACKGROUND: Hoddle, a biological control specialist in the Department of Entomology, collected colonies of Tamarixia during four recent trips to Pakistan. Twelve colonies of the biocontrol agent were quarantined at UCR. Safety testing showed that the parasites are disease-free and pose no environmental risk. The parasitic wasps do not bite or sting people or animals.

The ACP is found in parts of the Middle East, South and Central America, Mexico and the Caribbean. In the United States, the ACP was first detected in Florida in 1998; it is now found in Louisiana, Georgia, South Carolina, Texas and Arizona. In California, the pest was first detected in San Diego and Imperial county backyard trees. ACP is now well established in urban areas of Los Angeles, San Bernardino and Riverside counties.

When the ACP feeds on citrus leaves and stems, it damages the tree by injecting a toxin that causes leaves to twist and die. The ACP spreads citrus greening, or Huanglongbing disease, a deadly citrus disease. Leaves on infected trees turn yellow, the fruit turns bitter and eventually the tree dies. To date there is no known cure.

So far, Huanglongbing has not been detected in California (it has been detected in Mexico and Florida).

OTHER: Tamarixia will not eradicate ACP, but provide control by reducing the ACP population. It will perform an important role in backyard gardens and organic citrus groves where pesticide use is either difficult or unwanted. It is anticipated that commercial citrus producers in California will still need to apply insecticides for ACP control; the frequencies of these applications, however, are likely to be reduced because Tamarixia will be killing ACP nymphs that would have otherwise grown into adults in the absence of this natural enemy.
An adult Asian citrus psyllid and a nymph (seen just below the adult). Photo credit: Mike Lewis, CISR, UC Riverside.Enlarge

An adult Asian citrus psyllid and a nymph (seen just below the adult). Photo credit: Mike Lewis, CISR, UC Riverside.

An Asian citrus psyllid nymph.  Photo credit: Mike Lewis, CISR, UC Riverside.Enlarge

An Asian citrus psyllid nymph. Photo credit: Mike Lewis, CISR, UC Riverside.

A male <i>Tamarixia radiata</i>. Photo credit: Jason Mottern, UC Riverside.Enlarge

A male Tamarixia radiata. Photo credit: Jason Mottern, UC Riverside.

Map of the biocontrol grove at UC Riverside.  The release of <i>Tamarixia radiata</i> will take place in section A.  Image credit: Charles Farrar, Agricultural Operations, UC Riverside.Enlarge

Map of the biocontrol grove at UC Riverside. The release of Tamarixia radiata will take place in section A. Image credit: Charles Farrar, Agricultural Operations, UC Riverside.

Mark Hoddle is the director of UCR’s Center for Invasive Species Research.  Photo credit: L. Duka.Enlarge

Mark Hoddle is the director of UCR’s Center for Invasive Species Research. Photo credit: L. Duka.

The University of California, Riverside (www.ucr.edu) is a doctoral research university, a living laboratory for groundbreaking exploration of issues critical to Inland Southern California, the state and communities around the world. Reflecting California's diverse culture, UCR's enrollment has exceeded 21,000 students. The campus opened a medical school in 2013 and has reached the heart of the Coachella Valley by way of the UCR Palm Desert Center. The campus has an annual statewide economic impact of more than $1 billion.

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