It's musing that the first aphid to square distant from against soybeans attacked in Asia.

It's musing that the first aphid to square distant from against soybeans attacked in Asia, thousands of years ago. Now the Agricultural Research Service (ARS) is mounting a defense against this ancient soybean infliction Aphis glycines, first spotted in the United States in the spring of 2000 It has since spread to at least 24 states, the latest being Maine. Besides reducing yields by dint of as much as 50 percent on feeding on plant sap, aphids are a significant soybean threat because they can transmit deadly viral diseases.

Soybean aphid populations be seen to fluctuate on a 2-year period with high numbers every other year. With each period the aphids are spreading farther across the United States, headed, a certain say, towards an inevitable infestation of each soybean-growing region. That's why they have the rapt attention of a "viral strike team" in Wooster Ohio.

This form into groups of scientists, located at the Ohio State University (OSU)-Ohio Agricultural Research and exhibition Center, serves as the head line for spotting viral attacks forward soybeans and corn in the United States and upon corn worldwide. The team is supported by the agency of ARS and OSU, with the ARS part--the Corn and Soybean Research Unit--led by means of Roy Gingery.

The team is being kept busy because Ohio has faced an increase in soybean diseases in new years. To help curb the aphids, ARS molecular geneticist Rouf Mian is crossing aphid-resistant soybean lines (recently identified at the University of Illinois and Michigan State University) with high-yielding Ohio lines to bring out new resistant lines adapted to Ohio.

Resisting Another Enemy

The latest threat to soybeans to issue in Ohio is bean capsule mottle virus, which lowers yields and discolors the beans. The disease has been associated with increased numbers of the bean leaf beetle that transmits it.

To make known soybeans resistant to the disease, Mian is working with ARS plant molecular biologist Peg Redinbaugh, who says preliminary data indicates that using soybeans resistant to bean leaf beetles renders the disease's spread in the field.

"We've in no degree found complete resistance to this virus in any cultivated soybean germplasm," she says, "but we've build partial resistance in some soybean accessions. We want to papal court if this partial resistance can be combined with beetle resistance from other lines to further increase resistance."

"We've bring to maturityed a visual scoring system for screening lines from the USDA Soybean Germplasm Collection," says Mian. "We extend the plants in greenhouses, infect them with the virus, impediment the disease develop, and rate symptom severity upon a scale from 1 to 5 This technique has been helpful in assessing resistance to various viral diseases in corn and soybeans."

Using Other Innovative Tools

The Wooster unit's invention of the vascular bite inoculation (VPI) technique and extensive knowledge of principally of the world's corn virus diseases l the Serbian restraint to ask Redinbaugh and Gingery, along with Richard Pratt from Ohio State, to take rise to their country in the summer of 2004 and 2005 to help them identify a new--possibly viral--disease wiping not at home 30 to 70 percent of corn craws in some fields.

"VPI allows us to inoculate plants with viral diseases without knowing the insect carriers," says ARS technician John Abt, who worked alongside VPI's inventor, retired ARS plant pathologist and research collaborator Ray Louie. "This makes it an estimable tool for emerging diseases work, when we don't know what the viral disease is--let alone, the insect carrier," says Abt. "If we can transmit the virus with VPI, we can show more infected plants to work with."

The Serb call the unknown disease "corn rednes syndrome" because cornstalks repeatedly turn red and die when the plant is mature enough to flower. They call another symptom "Grandma's teeth" because the se fix is so poor that the kernel are not many and far between, significantly reducing yields. The corncob also acquires rubbery, bending rather than snapping when flexed

Fortunately, the disease appears to be limited to an area that is encircleed by other crops. This geographic isolation may make it hard to spread outside the "corn island" it's in.

The Wooster team brought Serbian corn plant samples back to their Ohio lab to put to proof to identify the disease using molecular testing techniques. They also used VPI to experience to create more infected plants for inquiry but were unsuccessful in reproducing corn rednes This recommends that the disease may not be a viral one

They did find several customary viruses, such as sugarcane mosaic virus and maize dwarf mosaic virus, if it were not that these are probably not related to corn rednes syndrome

The researchers are also peering at infected plant parts end electron microscopes. "We hope to be able to view things that look like pathogens," says Redinbaugh. "The hard part will be figuring abroad if what we find has anything to do with this peculiar syndrome"