Lexington, Kentucky
October 17, 2007
Since 2000, the soybean aphid has
caused many soybean producers in the United States a
considerable amount of grief. The pest, native to eastern Asia,
has spread to at least 20 states and provinces in the USA and
eastern Canada, causing more than $600 million in crop damage.
Add to that a $12 per acre cost of spraying fields to combat the
aphid, and the soybean industry is dealing with a total cost of
more than $750 million, which is increasing each year.
Researchers at the University of
Kentucky and Purdue
University are collaborating with the U.S. Department of
Agriculture to find ways to win the soybean aphid battle.
“Before the soybean aphid was found in the United States,
soybeans in the Midwest had rarely been attacked by a major
pest” said James Harwood, UK College of Agriculture assistant
professor of arthropod ecology. “So we’re trying to find ways
now to control this pest, and we are looking at natural
predators of the soybean aphid.”
Harwood and his colleagues are hoping their research, published
in the October issue of Molecular Ecology, will provide a
breakthrough in the fight against this invasive pest.
Through this research, an abundance of one of the soybean
aphid’s natural enemies – the insidious flower bug – has been
observed, especially early in the growing season. The flower bug
feeds on the soybean aphid, among other things, and Harwood
believes the bug may hold great potential in helping to control
this major pest.
“We’re trying to find out if the bug is really feeding on the
soybean aphid, and if so, how often. So we collect these bugs
from soybean fields and examine their guts for soybean aphid
DNA,” Harwood said. “Basically, we want to see who is eating
whom.
“What we are seeing is that the predator (flower bug) is already
there before the aphid arrives,” he continued. “So when the
aphid does arrive, the predatory flower bugs feed on the aphids
and potentially slow their rapid population growth.”
Harwood said the insidious flower bug is common throughout much
of the eastern and central United States, and the question is
really one of how to enhance its populations in soybean fields.
“We’re very interested in their ecology - what food resources
they use and how they interact with other predators in the same
location,” he said. “We have to also find out if manipulating
biodiversity by providing alternative food sources has a major
effect on the ability of these predators to feed on the soybean
aphid. The last thing we want to do is distract it from the pest
we want it to eat.”
Biodiversity is defined as the number and variety of organisms
found within a specified geographic region.
Although the soybean aphid generally has not risen to damaging
levels in Kentucky, the research could still benefit the state’s
soybean producers.
“We need to find out why the soybean aphid population has a
persistently low density in Kentucky,” Harwood said. “There’s no
way to say there’s no chance of a sudden soybean aphid
population explosion in Kentucky, and so we are trying to be
proactive and keep that from happening.
“The soybean aphid’s main impact starts just a couple of hours
north of here,” he continued. “Our neighbors in Indiana are
having a tough time of it, so hopefully this research will give
them the tools to fight it.”
Harwood said the soybean aphid problem is not going away. In
fact, each year more producers in the major soybean producing
states have to deal with the pest. If the soybean aphid
populations are large, producers can see yield losses of up to
50 percent. Harwood said his team is looking not only at the
insidious flower bug but at other natural predators, and how
they interact with the soybean aphid.
“Really, for Kentucky, this research will hopefully serve as a
model system,” he said. “If we know how to combat something like
the soybean aphid, we can impact other invasive species as they
arrive.”
UK College of Agriculture, through its land-grant mission,
reaches across the commonwealth with teaching, research and
extension to enhance the lives of Kentuckians.
By Aimee Nielson |
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