Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Scientists Find New Way to Assess Where Cotton-Killing Pests Develop

04.12.2002


In a finding that could have broad implications for farmers’ ability to stop pests from decimating cotton crops, scientists from North Carolina State University and agricultural research stations in the Cotton Belt have developed a new technique to determine where the larvae of certain agricultural pests develop.



The study, which looks at the characteristics of the moths that the larvae turn into, shows that a large majority of late-season moths in the Cotton Belt - specifically Helicoverpa zea, a major pest of cotton commonly known as the cotton bollworm - are not developing on cotton and soybean plants, as the prevailing theory suggests, but are developing instead on plants like corn.

The research suggests that this non-toxic corn, therefore, provides a major refuge for H. zea moths, and as such is critical to halting the evolution of insecticide-immune pests, perhaps more so than existing small cotton refuges.


The scientists published their work in Proceedings of the National Academy of Sciences.

Although it seems counterintuitive, non-toxic refuges are essential to controlling pests like the cotton bollworm because the pests that come from these refuges have little to no immunity to toxins. It is estimated that about 80 to 95 percent of cotton bollworms are killed by transgenic cotton plants that produce Bt toxin - derived from the bacterium Bacillus thuringiensis - leaving a fair number of potentially immune caterpillars moving about. When these immune pests mate with pests from non-toxic plants, offspring are not immune to the Bt toxin, and are likely susceptible to die a Bt toxin-induced death.

The scientists - including NC State’s Dr. Fred Gould, William Neal Reynolds Professor of entomology, and Dr. Neal Blair, professor of marine, earth and atmospheric sciences; representatives from the USDA’s Southern Crops Research Lab in College Station, Texas, and the Louisiana Agricultural Experiment Station in Bossier City, La.; and two NC State students -used a novel technique called stable isotope assessment to gauge the origination of moths in late summer. The work was supported by the USDA Biotechnology Risk Assessment Program and the W.M. Keck Center for Behavioral Biology.

The scientists compared the ratios of carbon isotopes 13C and 12C in moths captured over three- and four-year periods from August to October in areas of Louisiana and Texas. These so-called stable isotopes are present in every living organism and in the air. Plants with a certain type of photosynthesis - those with C3 physiology, like cotton - are more depleted in 13C relative to 12C than plants with C4 physiology, like corn. Thus, looking at these ratios in moth wing tissue can provide clues to where the moths grew up, the researchers assert.

And knowing where the moths develop gives researchers clues to how refuges - plants that are not treated with insecticides - are working to put the brakes on the evolution of pests that are genetically resistant to insecticides.

Currently, about 60 percent of cotton grown in the Cotton Belt contains Bt toxin. The Environmental Protection Agency allows the planting of 50 percent Bt corn in cotton-growing areas, as opposed to 80 percent Bt corn in regions where cotton is not grown, Gould says. This policy assumes that H. zea moths migrate from the Cotton Belt to northern Corn Belt states in the summer, but do not return in the fall.

But, since less than 50 percent of late-season moths captured in the study were fed as larvae on cotton, they may be migrating from the Corn Belt, Gould says. This means the traditional assumptions about late-season H. zea moths - that they grow up on cotton, migrate to northern Corn Belt states and then die - seem to be wrong.

"Corn is most likely serving as the predominant alternate C4 host for H. zea," the paper asserts. "Currently, less than 25 percent of U.S. corn produces Bt toxin. If, in the future, most field corn planted in the northern and southern United States remains in non-Bt producing varieties, it could serve as a major H. zea refuge. Maintaining the current limit of 50 percent non-Bt corn in cotton-growing areas therefore seems appropriate for maintaining the long-term utility of Bt cotton."

"In the short term, this is good news for cotton farmers," Gould says. "It shows that corn can provide a refuge so cotton farmers don’t have to increase the non-toxic cotton refuge."

Gould says that problems can set in if Bt corn begins becoming ubiquitous in the Corn Belt. Fewer refuge plants - non-Bt corn, in this case - could allow pests’ resistance to Bt toxin to evolve more quickly, he says.

Dr. Fred Gould | EurekAlert!
Further information:
http://www.ncsu.edu/news/press_releases/02_12/317.htm

More articles from Agricultural and Forestry Science:

nachricht New research recovers nutrients from seafood process water
31.10.2018 | Chalmers University of Technology

nachricht Plant Hormone Makes Space Farming a Possibility
17.10.2018 | Universität Zürich

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: Nonstop Tranport of Cargo in Nanomachines

Max Planck researchers revel the nano-structure of molecular trains and the reason for smooth transport in cellular antennas.

Moving around, sensing the extracellular environment, and signaling to other cells are important for a cell to function properly. Responsible for those tasks...

Im Focus: UNH scientists help provide first-ever views of elusive energy explosion

Researchers at the University of New Hampshire have captured a difficult-to-view singular event involving "magnetic reconnection"--the process by which sparse particles and energy around Earth collide producing a quick but mighty explosion--in the Earth's magnetotail, the magnetic environment that trails behind the planet.

Magnetic reconnection has remained a bit of a mystery to scientists. They know it exists and have documented the effects that the energy explosions can...

Im Focus: A Chip with Blood Vessels

Biochips have been developed at TU Wien (Vienna), on which tissue can be produced and examined. This allows supplying the tissue with different substances in a very controlled way.

Cultivating human cells in the Petri dish is not a big challenge today. Producing artificial tissue, however, permeated by fine blood vessels, is a much more...

Im Focus: A Leap Into Quantum Technology

Faster and secure data communication: This is the goal of a new joint project involving physicists from the University of Würzburg. The German Federal Ministry of Education and Research funds the project with 14.8 million euro.

In our digital world data security and secure communication are becoming more and more important. Quantum communication is a promising approach to achieve...

Im Focus: Research icebreaker Polarstern begins the Antarctic season

What does it look like below the ice shelf of the calved massive iceberg A68?

On Saturday, 10 November 2018, the research icebreaker Polarstern will leave its homeport of Bremerhaven, bound for Cape Town, South Africa.

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

Optical Coherence Tomography: German-Japanese Research Alliance hosted Medical Imaging Conference

19.11.2018 | Event News

“3rd Conference on Laser Polishing – LaP 2018” Attracts International Experts and Users

09.11.2018 | Event News

On the brain’s ability to find the right direction

06.11.2018 | Event News

 
Latest News

Nonstop Tranport of Cargo in Nanomachines

20.11.2018 | Life Sciences

Researchers find social cultures in chimpanzees

20.11.2018 | Life Sciences

When AI and optoelectronics meet: Researchers take control of light properties

20.11.2018 | Physics and Astronomy

VideoLinks
Science & Research
Overview of more VideoLinks >>>