ForumProtecting Crops From Alien
Increased travel and global trade have steadily increased the threat of not only
human disease epidemics, but also plant disease and pest epidemics. Never before
have so many new and nonnative insects, viruses, and plant diseases shown up so
rapidly in this country. This is especially true of soybean pests.
Close-up of vascular puncture inoculation. Fine pins are passed through
a virus-containing (green) extract and then into a corn kernel to inoculate
the kernel with the virus.
Since soybeans are a relatively new crop in the United States, especially as
a major crop, its taken quite a while for its foreign enemies to find
it, as was predicted decades ago. For example, the first aphids that attack
soybeans were found in this country just 5 years ago. They seem to have first
arrived in Chicago, a center of global trade, aboard a plane or ship. Lacking
natural controls, theyve spread so rapidly since then that its now
hard to find a midwestern county that doesnt have them.
Like all aphids, soybean aphids spread several plant viral diseases. They also
diminish yields by sucking sugar water from the plants. They seem to be on a
2-year cycle, and we expect 2005 to be one of the high-infestation years.
In the summer of 2004, soybean rust appeared here for the first time. A fungal
disease, it is thought to have been importednot by trade or by travelbut
by bad weather. Strong hurricanes are believed to have carried the rust-causing
spores into soy-production areas.
Since any imports can carry foreign aphids or other pests that attack farm
crops, great efforts are made to inspect all incoming shipments at various points
of entryand to intercept any potential trouble-making plant pest detected.
But few people know that in the 1960swell before there was an Animal
and Plant Health Inspection Service or Office of Homeland Security to enforce
that inspection responsibilitya joint ARS-state
team of scientists was formed in Wooster, Ohio. For more than 40 years, its
been serving as a first line of defense against pest invaders of soybean, corn,
and other farm crops.
As described in the story that begins on page 4, the teams original task
was to cope with a corn disease epidemic. By the time it was formed, USDA and
state researchers and specialists were already working together nationally to
battle pests of corn, wheat, and alfalfathe dominant crops at the time.
Since soybeans were just coming into their own, state and ARS researchers were
ready when the cropand its pestsbegan to explode in numbers.
The ARS-Ohio State University (OSU) pest detection team is an excellent example
of the longstanding cooperation between federal and state governments that marks
ARS research nationwide. The ARS part of the team specializes in protecting
against viruses. Together the team members contribute a wealth of resources,
including expertise in cloning, genetics, entomology, and plant biology and
pathology. They are all located at OSUs Ohio Agricultural Research and
Development Center in Wooster.
Many ARS labs are located on or near such facilities, which include state universities
and experiment and extension stations. At Wooster, state and ARS experts constantly
work side by side. When there was a report of a possible corn virus outbreak
in Serbia, OSU maize researcher Rich Pratt joined ARS plant pathologist Peg
Redinbaugh and research leader Roy Gingery on a trip there to study samples
and share techniques.
In another cooperative effort, Ron Hammond, an entomologist with the OSU extension
service, monitored the soybean aphid invasion in Ohio, working with extension
specialists throughout the Midwest and with ARS scientists. He serves on an
agronomic crops team of extension agents, state specialists, and researchers.
Hammond was part of the first generation of entomologists trained to fight
soybean insect pests. From his first days on the job in 1979, he worked closely
with ARSs Dick Cooper, who specialized in soybean breeding research at
Wooster. Cooper has since retired, but the federal-state cooperation continues
to this dayas it does nationwideto protect soybeans, along with
corn and other U.S. crops.
One of the new pests to reach Ohio in recent years is the bean leaf beetle,
which has long infested other states, carrying with it bean pod mottle virus.
Hammond and other state scientists and specialists joined forces with the ARS
viral team to control the beetle and breed resistance in soybeans to the virus
it spreads. The newest member of the Wooster team, molecular geneticist Rouf
Mian, has already been working closely with OSU, serving on the bean leaf beetle
Despite all these efforts and successes nationally and internationally, plant
diseases alone still cause more than $9 billion in annual losses in the United
States. Plant pathogens keep evolving and overcoming once-effective management
tactics even as they move from state to state and country to country. ARS scientists
will continue to work closely with programs in Ohio and in 27 other states as
part of our ongoing national plant-disease research program to devise effective
management strategies to keep up with the fast-changing disease situation.
ARS National Program Leader
General Biological Science and Plant Health
"Forum" was published in the May
2005 issue of Agricultural Research magazine.