Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Killing Crop-Eating Pests: Compounds Work by Disrupting Bugs' Winter Sleep

29.09.2011
The creation of compounds that disrupt a worldwide pest's winter sleep hints at the potential to develop natural and targeted controls against crop-eating insects, new research suggests.

Scientists have designed agents that interfere with the protective dormancy period of the corn earworm, a species that infests more than 100 types of plants and costs American farmers an estimated $2 billion a year in losses and control costs.

The compounds, composed of synthetic molecules that mimic the structure of a hormone in these insects, have three different effects on diapause, a hibernation-like state of arrested development that allows many types of bugs to survive through the winter. The agents can force the insects out of diapause prematurely, prevent the bugs from ever entering diapause, or block the termination of diapause.

Any of these cases could be described as "ecological suicide," said David Denlinger, professor of entomology and evolution, ecology and organismal biology at Ohio State University and senior author of the study.

"Diapause is such an important aspect of the life cycle," Denlinger said. "If we can do anything to disrupt the timing of that, make them go into diapause at the wrong time or break them out too early when there is no food available, that would be a pretty effective tool and a possible control strategy.

"And we now have tools that can do all three of those things to manipulate diapause."

The research is published online ahead of print in the Proceedings of the National Academy of Sciences.

The period of diapause in insects is controlled in part by the diapause hormone. In the corn earworm, Helicoverpa zea, and other crop pests, the hormone has been shown to break diapause, essentially waking up the bugs from their pupal state after they have been protectively burrowed underground during cold weather. In some other species, the diapause hormone initiates the hibernation instead.

Denlinger and colleagues investigated the structure of the hormone in these insects, and discovered that seven core amino acids do most of the work of terminating diapause. They then created chemical compounds based on the structure of that portion of the hormone and tested their effects on corn earworm larvae and pupae raised in a laboratory.

"By mimicking the structure of the amino acids, these compounds trick the body into responding as if the hormone is activated," said Qirui Zhang, a postdoctoral researcher in entomology and evolution, ecology and organismal biology at Ohio State and first author of the paper.

The researchers have narrowed the current crop of molecules down to three that appear to have the most potent effects at three different stages in the corn earworm's life. In at least one case, the science has improved on nature: The compound that terminates diapause prematurely is about 50 times more potent than an injection of the natural diapause hormone.

One other compound was so strong that it outright killed the larvae before there was any chance to disrupt their diapause state.

"That's not actually as interesting to us because we're looking at how to manipulate diapause," Denlinger said. "These agents wouldn't necessarily kill them right away, but interfering with diapause takes away their protection that gets them through adverse times and makes them vulnerable to environmental conditions."

Controlling these pests while they are larvae - which is when they do the most damage to plants - is desirable because once they pupate, they are underground and inaccessible, Denlinger noted.

But then again, terminating diapause early means pupae will die of exposure or starvation and won't have the chance to become adult moths that lay eggs and begin the life cycle all over again, he said.

In the experiments for this paper, the compounds were injected into the insects. Zhang is leading current experiments to deliver the agents orally in the bugs' food. Denlinger envisions the use of these compounds in some other form for insect control on a massive scale - perhaps by incorporating them into transgenic plants.

Current control measures for the corn earworm include insecticides and transgenic plants - primarily cotton, and not food crops - that contain a toxin that is deadly to the pest.

The research group will continue to work on refining the molecules and testing their effectiveness. "My guess is that these particular compounds won't be the ones that solve the world's problems, but this points us in the direction that could lead to some next-generation control agents," Denlinger said.

This work was supported by grants from the U.S. Department of Agriculture and the U.S.-Israel Binational Agricultural Research and Development Fund.

Additional co-authors include Ronald Nachman, Krzysztof Kaczmarek and Janusz Zabrocki of the U.S. Department of Agriculture-Agriculture Research Service in College Station, Texas; Kaczmarek and Zabrocki also are affiliated with Technical University of Lodz in Poland.

Contact: David Denlinger, (614) 292-6425; denlinger.1@osu.edu
Written by Emily Caldwell, (614) 292-8310; caldwell.151@osu.edu

Emily Caldwell | Newswise Science News
Further information:
http://www.osu.edu

More articles from Agricultural and Forestry Science:

nachricht Researchers discover a new link to fight billion-dollar threat to soybean production
14.02.2017 | University of Missouri-Columbia

nachricht Important to maintain a diversity of habitats in the sea
14.02.2017 | University of Gothenburg

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: Breakthrough with a chain of gold atoms

In the field of nanoscience, an international team of physicists with participants from Konstanz has achieved a breakthrough in understanding heat transport

In the field of nanoscience, an international team of physicists with participants from Konstanz has achieved a breakthrough in understanding heat transport

Im Focus: DNA repair: a new letter in the cell alphabet

Results reveal how discoveries may be hidden in scientific “blind spots”

Cells need to repair damaged DNA in our genes to prevent the development of cancer and other diseases. Our cells therefore activate and send “repair-proteins”...

Im Focus: Dresdner scientists print tomorrow’s world

The Fraunhofer IWS Dresden and Technische Universität Dresden inaugurated their jointly operated Center for Additive Manufacturing Dresden (AMCD) with a festive ceremony on February 7, 2017. Scientists from various disciplines perform research on materials, additive manufacturing processes and innovative technologies, which build up components in a layer by layer process. This technology opens up new horizons for component design and combinations of functions. For example during fabrication, electrical conductors and sensors are already able to be additively manufactured into components. They provide information about stress conditions of a product during operation.

The 3D-printing technology, or additive manufacturing as it is often called, has long made the step out of scientific research laboratories into industrial...

Im Focus: Mimicking nature's cellular architectures via 3-D printing

Research offers new level of control over the structure of 3-D printed materials

Nature does amazing things with limited design materials. Grass, for example, can support its own weight, resist strong wind loads, and recover after being...

Im Focus: Three Magnetic States for Each Hole

Nanometer-scale magnetic perforated grids could create new possibilities for computing. Together with international colleagues, scientists from the Helmholtz Zentrum Dresden-Rossendorf (HZDR) have shown how a cobalt grid can be reliably programmed at room temperature. In addition they discovered that for every hole ("antidot") three magnetic states can be configured. The results have been published in the journal "Scientific Reports".

Physicist Dr. Rantej Bali from the HZDR, together with scientists from Singapore and Australia, designed a special grid structure in a thin layer of cobalt in...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Booth and panel discussion – The Lindau Nobel Laureate Meetings at the AAAS 2017 Annual Meeting

13.02.2017 | Event News

Complex Loading versus Hidden Reserves

10.02.2017 | Event News

International Conference on Crystal Growth in Freiburg

09.02.2017 | Event News

 
Latest News

Biocompatible 3-D tracking system has potential to improve robot-assisted surgery

17.02.2017 | Medical Engineering

Real-time MRI analysis powered by supercomputers

17.02.2017 | Medical Engineering

Antibiotic effective against drug-resistant bacteria in pediatric skin infections

17.02.2017 | Health and Medicine

VideoLinks
B2B-VideoLinks
More VideoLinks >>>