Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

How safe is the enemy of a citrus-threatening pest?

05.02.2014
UC Riverside study shows Tamarixia radiata, a natural enemy of the Asian citrus psyllid, poses negligible environmental risk

The Asian citrus psyllid (ACP) can spread the lethal and incurable citrus disease known as huanglongbing (HLB) or citrus greening that threatens the multi-billion dollar global citrus industry. In Southern California, large and widespread populations of ACP have been detected in several counties, having arrived, most likely, from Mexico where ACP is widely established.


This is a female Tamarixia radiata, highly magnified. The tiny parasitic wasp lays eggs in Asian citrus psyllid nymphs, eventually killing them.

Credit: Jason Mottern, UC Riverside


This photo shows an Asian citrus psyllid nymph.

Credit: Mike Lewis, CISR, UC Riverside.

In 2011, for the first time entomologists at the University of California, Riverside released Tamarixia radiata, a wasp that is the natural enemy of the ACP, in a citrus grove in Riverside to help control the psyllid. But is this wasp safe to use? Does its introduction pose any risk to the environment?

Results from Federally mandated tests performed at the University of California, Riverside now show that Tamarixia radiata is indeed safe for the environment and poses no undue risk to other insects, humans or pets.

"Our work demonstrates that Tamarixia radiata is very specific to the target it is being released to kill — the nymphs of the Asian citrus psyllid in this case," said Mark Hoddle, the director of the Center for Invasive Species Research, whose lab performed the tests.

Study results appear in the February 2014 issue of the Journal of Economic Entomology.

Safety testing in biological control is important as the release of natural enemies may pose some type of environmental risk. In this instance, Tamarixia radiata were imported from the Punjab region of Pakistan, and tested for safety in quarantine at UCR over an 18 month period.

The study is the first published study designed specifically to determine the host range of Tamarixia radiata. The results are important as the wasp is being used for ACP biological control in Florida, Texas, the Caribbean, Central and South America, and Mexico.

"These types of studies continue to advance the safety of biological control for suppressing populations of invasive pests thereby greatly reducing reliance on pesticides for control," said Hoddle, a biological control specialist in the Department of Entomology. "In urban areas, initially pesticide treatments were applied to ACP-infested trees, and chemically-treated buffer zones were established around sites to control the pest."

To test the safety of Tamarixia, different species of native California psyllids were exposed to the wasp in a series of tests. The tests were designed to give the wasp a "choice" between ACP and a non-target psyllid speices, or there was "no choice" (that is, the wasp was only given access to a non-target species, one it had not evolved with). When given a choice, Tamarixia overwhelming attacked ACP, the researchers found.

"In only one instance was a non-target species attacked at very low rates — less than 5 percent," Hoddle said. "This was the native pest potato psyllid, which spreads a bacterium that causes zebra chip disease. Such low attack rates are unlikely to cause population declines of this pest."

According to Hoddle, such results demonstrate that carefully selected natural enemies used in biological control programs for invasive pests can be very safe and should not cause unwanted environmental damage.

"There is growing concern over the damage that invasive species cause," he said, "and biological control programs don't want to be causing additional problems through releasing inappropriate agents for the control of invasive pests. Safety tests like those conducted in this study greatly minimize these risks."

Hoddle noted that the tests were difficult to conduct in quarantine.

"Native psyllids are hard to find and the native plants they grow on are difficult to culture in the laboratory," he said. "It was very rewarding to have completed these demanding studies over an 18 month period and to discover that the Pakistani wasp will be a good natural enemy to use in California for the biological control of ACP."

In 2011, the U.S. Department of Agriculture reviewed and approved the 60-page Environment Assessment Report, the foundational work that the research paper is based on, and approved release of Tamarixia from quarantine. The data presented in the report is essentially the same as the published paper except that this time it was reviewed by additional scientists.

"We have now released more than 200,000 Tamarixia radiata in Southern California at more than 350 different sites, mainly in urban areas and spanning six counties — Imperial, Los Angeles, Orange, Riverside, San Bernardino, and San Diego," Hoddle said. "They have established and are spreading, tracking down ACP on citrus in people's gardens and orchards."

The Tamarixia larvae will eat the ACP nymphs, killing them, and emerge as adults about 12 days later. Adult female Tamarixia also eat other ACP nymphs, killing many in the process.

Hoddle was joined in the study by Raju Pandey, a former postdoctoral researcher in his lab and working now with the Citrus Research Board.

The research was supported by a California Department of Food and Agriculture Specialty Crops Grant and a Citrus Research Board grant.

The University of California, Riverside 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. A broadcast studio with fiber cable to the AT&T Hollywood hub is available for live or taped interviews. UCR also has ISDN for radio interviews. To learn more, call (951) UCR-NEWS.

Iqbal Pittalwala | EurekAlert!
Further information:
http://www.ucr.edu

More articles from Agricultural and Forestry Science:

nachricht Crop advances grow with protection
28.04.2016 | American Society of Agronomy

nachricht Can urban gardeners benefit ecosystems while keeping food traditions alive?
06.04.2016 | University of Illinois College of Agricultural, Consumer and Environmental Sciences

All articles from Agricultural and Forestry Science >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Nuclear Pores Captured on Film

Using an ultra fast-scanning atomic force microscope, a team of researchers from the University of Basel has filmed “living” nuclear pore complexes at work for the first time. Nuclear pores are molecular machines that control the traffic entering or exiting the cell nucleus. In their article published in Nature Nanotechnology, the researchers explain how the passage of unwanted molecules is prevented by rapidly moving molecular “tentacles” inside the pore.

Using high-speed AFM, Roderick Lim, Argovia Professor at the Biozentrum and the Swiss Nanoscience Institute of the University of Basel, has not only directly...

Im Focus: 2+1 is Not Always 3 - In the microworld unity is not always strength

If a person pushes a broken-down car alone, there is a certain effect. If another person helps, the result is the sum of their efforts. If two micro-particles are pushing another microparticle, however, the resulting effect may not necessarily be the sum their efforts. A recent study published in Nature Communications, measured this odd effect that scientists call “many body.”

In the microscopic world, where the modern miniaturized machines at the new frontiers of technology operate, as long as we are in the presence of two...

Im Focus: Tiny microbots that can clean up water

Researchers from the Max Planck Institute Stuttgart have developed self-propelled tiny ‘microbots’ that can remove lead or organic pollution from contaminated water.

Working with colleagues in Barcelona and Singapore, Samuel Sánchez’s group used graphene oxide to make their microscale motors, which are able to adsorb lead...

Im Focus: ORNL researchers discover new state of water molecule

Neutron scattering and computational modeling have revealed unique and unexpected behavior of water molecules under extreme confinement that is unmatched by any known gas, liquid or solid states.

In a paper published in Physical Review Letters, researchers at the Department of Energy's Oak Ridge National Laboratory describe a new tunneling state of...

Im Focus: Bionic Lightweight Design researchers of the Alfred Wegener Institute at Hannover Messe 2016

Honeycomb structures as the basic building block for industrial applications presented using holo pyramid

Researchers of the Alfred Wegener Institute (AWI) will introduce their latest developments in the field of bionic lightweight design at Hannover Messe from 25...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

The “AC21 International Forum 2016” is About to Begin

27.04.2016 | Event News

Soft switching combines efficiency and improved electro-magnetic compatibility

15.04.2016 | Event News

Grid-Supportive Buildings Give Boost to Renewable Energy Integration

12.04.2016 | Event News

 
Latest News

Expanding tropics pushing high altitude clouds towards poles, NASA study finds

06.05.2016 | Earth Sciences

IU-led study reveals new insights into light color sensing and transfer of genetic traits

06.05.2016 | Life Sciences

Thievish hoverfly steals prey from carnivorous sundews

06.05.2016 | Life Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>