Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Techniques available to detect soil that inhibits destructive soybean pest

04.07.2005


Female soybean cyst nematodes, attached to the roots of the plants and filled with eggs, are white. The nematodes turn brown as their bodies become cysts harboring the eggs that hatch into juveniles, which continue the cycle of stealing nutrients from the plants. (Photo/Andreas Westphal, Purdue University)


Identification of soils that inhibit a tiny soybean-destroying organism is an important tool in reducing yield losses, according to a Purdue University plant pathologist.

Soybean cyst nematodes cause between $800 million and $1 billion annually in crop losses in the United States, according the American Phytopathological Society. However, techniques are available to find soils that specifically suppress these microscopic roundworms, said Andreas Westphal, assistant professor of plant pathology. The female nematodes are white, lemon-shaped parasites that become dead brown shells filled with maturing eggs. Some soils have as yet not-understood characteristics that don’t foster development of the pests.

Westphal, whose research focuses on soybean cyst nematodes and ways to thwart them, said that using nematode-suppressive soils is an easily implemented, environmentally friendly weapon in fighting the parasites, which are found worldwide in soybean-producing areas.



"Using plants bred to resist pests is not the complete answer, so it’s important to find suppressive mechanisms," Westphal said. "Bio-control is much more desirable than using chemicals in order to limit damage to the environment."

In a paper published in the just-released March 2005 issue of the Journal of Nematology, Westphal summarizes the techniques for identifying soil that specifically suppresses soybean cyst nematodes. He also discusses how to use nematode-suppressive soils to battle the root-dwelling pests and the limitations of the techniques.

In previous research on a different cyst nematode, Westphal and his colleagues determined that mixing 1 percent to 10 percent of nematode-suppressive soil into the top layer of a soybean field plot effectively decreased nematode activity. In addition, they know that viability of plants and soil richness, moisture and temperature can affect how active and numerous soybean cyst nematodes are in particular fields.

"A key find was that a small amount of suppressive soil or a cyst from a suppressive soil can lower nematode numbers," Westphal said. "We promote conditions in soil to suppress the nematode, and we also study the soil so that we can determine the mechanisms that create suppression."

Some types of fungi and other organisms help keep the soil healthy by feeding on nematodes. Whether a field is tilled can affect nematode population density, but it’s not yet known whether this is related to a change in the number of nematode-eating microbes, Westphal said. Further study is needed on how microbial communities function in order to determine conditions that contribute to nematode development.

Westphal was able to confirm the nematode supressiveness of soil by using treatments to eliminate soil organisms and other elements that inhibit nematode development. Another confirmation technique was to add suppressive soil to soils conducive to nematode development. The researchers also were able to document reduced nematode reproduction, population density, and whether certain types of soil were suppressive to specific pathogens.

"Currently, we are extending this research to finding ways to create more nematode suppression in soil," Westphal said. "This is important because nematode populations constantly change so they can overcome certain types of resistance, including even plants that are bred to be resistant to the organisms."

Westphal and his research team conducted a survey throughout Indiana to locate nematode-suppressive soils in an effort to make this tool more available and to further study the mechanisms that create its effectiveness against the pathogen.

Soybean cyst nematodes, one of a large, diverse group of multicellular organisms, are the most destructive soybean pathogen in the United States. The nematodes were first documented in Japan in the early 20th century and first reported in the United States in 1954. However, evolutionary biologists believe the pests were probably present in both areas as much as thousands of years earlier.

The females of the species use a short, hypodermic needle-like mouth to pierce soybean roots and suck out the nutrients. As the adult female ages, she fills with eggs, turns yellow and then brown to become the nematode cyst. At that point her body is a case to protect hundreds of eggs while they mature, hatch into juveniles and leave the cyst to further attack the plant roots. Swollen females can be seen with the naked eye, but worm-like juveniles and males can best be seen with a microscope.

As nematodes steal nutrients from the roots, the plants are weakened and don’t grow well. Subsequently, plants may be more vulnerable to attack by other stresses, such as insects, diseases and drought.

It’s often impossible to see symptoms of soybean cyst nematode damage, so soil and roots must be tested to reveal or confirm the pests’ presence. Infestation gradually causes progressively lower yields and the worst cases result in yellow and stunted soybean plants. Plants with severe, visible damage can occur in patches in highly infested fields.

There are no pesticides that will eradicate soybean cyst nematode, which also preys on other legumes and some grasses.

The United States Department of Agriculture is providing funding for Westphal’s study of the soybean cyst nematode.

Susan A. Steeves | EurekAlert!
Further information:
http://www.purdue.edu

More articles from Agricultural and Forestry Science:

nachricht Kakao in Monokultur verträgt Trockenheit besser als Kakao in Mischsystemen
18.09.2017 | Georg-August-Universität Göttingen

nachricht Ultrasound sensors make forage harvesters more reliable
28.08.2017 | Fraunhofer-Institut für Zerstörungsfreie Prüfverfahren IZFP

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: The pyrenoid is a carbon-fixing liquid droplet

Plants and algae use the enzyme Rubisco to fix carbon dioxide, removing it from the atmosphere and converting it into biomass. Algae have figured out a way to increase the efficiency of carbon fixation. They gather most of their Rubisco into a ball-shaped microcompartment called the pyrenoid, which they flood with a high local concentration of carbon dioxide. A team of scientists at Princeton University, the Carnegie Institution for Science, Stanford University and the Max Plank Institute of Biochemistry have unravelled the mysteries of how the pyrenoid is assembled. These insights can help to engineer crops that remove more carbon dioxide from the atmosphere while producing more food.

A warming planet

Im Focus: Highly precise wiring in the Cerebral Cortex

Our brains house extremely complex neuronal circuits, whose detailed structures are still largely unknown. This is especially true for the so-called cerebral cortex of mammals, where among other things vision, thoughts or spatial orientation are being computed. Here the rules by which nerve cells are connected to each other are only partly understood. A team of scientists around Moritz Helmstaedter at the Frankfiurt Max Planck Institute for Brain Research and Helene Schmidt (Humboldt University in Berlin) have now discovered a surprisingly precise nerve cell connectivity pattern in the part of the cerebral cortex that is responsible for orienting the individual animal or human in space.

The researchers report online in Nature (Schmidt et al., 2017. Axonal synapse sorting in medial entorhinal cortex, DOI: 10.1038/nature24005) that synapses in...

Im Focus: Tiny lasers from a gallery of whispers

New technique promises tunable laser devices

Whispering gallery mode (WGM) resonators are used to make tiny micro-lasers, sensors, switches, routers and other devices. These tiny structures rely on a...

Im Focus: Ultrafast snapshots of relaxing electrons in solids

Using ultrafast flashes of laser and x-ray radiation, scientists at the Max Planck Institute of Quantum Optics (Garching, Germany) took snapshots of the briefest electron motion inside a solid material to date. The electron motion lasted only 750 billionths of the billionth of a second before it fainted, setting a new record of human capability to capture ultrafast processes inside solids!

When x-rays shine onto solid materials or large molecules, an electron is pushed away from its original place near the nucleus of the atom, leaving a hole...

Im Focus: Quantum Sensors Decipher Magnetic Ordering in a New Semiconducting Material

For the first time, physicists have successfully imaged spiral magnetic ordering in a multiferroic material. These materials are considered highly promising candidates for future data storage media. The researchers were able to prove their findings using unique quantum sensors that were developed at Basel University and that can analyze electromagnetic fields on the nanometer scale. The results – obtained by scientists from the University of Basel’s Department of Physics, the Swiss Nanoscience Institute, the University of Montpellier and several laboratories from University Paris-Saclay – were recently published in the journal Nature.

Multiferroics are materials that simultaneously react to electric and magnetic fields. These two properties are rarely found together, and their combined...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

“Lasers in Composites Symposium” in Aachen – from Science to Application

19.09.2017 | Event News

I-ESA 2018 – Call for Papers

12.09.2017 | Event News

EMBO at Basel Life, a new conference on current and emerging life science research

06.09.2017 | Event News

 
Latest News

Rainbow colors reveal cell history: Uncovering β-cell heterogeneity

22.09.2017 | Life Sciences

Penn first in world to treat patient with new radiation technology

22.09.2017 | Medical Engineering

Calculating quietness

22.09.2017 | Physics and Astronomy

VideoLinks
B2B-VideoLinks
More VideoLinks >>>