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PRESS RELEASE
For immediate release
Image courtesy of the USDA-Agricultural Research Service. |
Plant Pathologists
Offer Soybean Rust Identification and Management Tips
St. Paul, Minn. (November 11, 2004) - With the confirmation that soybean rust
has been detected in the U.S., plant pathologists with The American
Phytopathological Society (APS) are offering insight into the management and
identification of this disease.
According to Doug Jardine, director of the APS Office of Public Affairs and
Education and plant pathology professor at Kansas State University, plant
pathologists from government agencies, industry, and universities have been
working together to prepare for the appearance of soybean rust in the U.S. for
the past two years. “Through this collaboration, we have been able to share
research information from around the world and updates on control methods, such
as fungicides sprays and predictive weather models,” said Jardine. Plant
pathologists have also worked with local extension agents and growers to educate
them on disease identification, potential yield loss, and costs associated with
managing the disease.
Plant pathologists do not expect soybean rust to affect all soybean growing
areas next year. “Growers should not assume that every soybean field will be in
danger,” said Jardine. “Based on our models, the disease is expected to be more
severe in the Southeast, Lower Mississippi-Delta region, and the Appalachians
and less severe in the western Great Plains and northern Great Lakes area,” he
said.
Soybean rust is caused by two fungal species—Phakopsora pachyrhizi and
Phakopsora meibomiae. The more aggressive species, Phakopsora pachyrhizi, is the
type that has been detected in the U.S.
Soybean rust primarily affects plant leaves and creates two types of lesions—tan
and red lesions with tan being the most severe. The appearance of brown spots on
soybean leaves is the first sign of infection. When the leaf is turned over, a
plant infected with soybean rust will have raised pustules with rust spores
inside. As rust severity increases, premature defoliation and early maturation
of plants is common. Soybean rust can go from a few pustules in a field to full
field defoliation in a matter of about two weeks.
The main method of controlling soybean rust is through early detection and
application of fungicides, said Jardine. “If the disease goes undetected for too
long, the fungicides will not have much of an effect,” he said. “Growers must
put fungicides on as a preventive measure or at the earliest sign of infection,”
said Jardine. Information on available fungicides, rates, and time of
application can be obtained through local Cooperative Extension Service offices.
Fungicide companies and the Environmental Protection Agency (EPA) are working
closely with plant pathologists and growers to provide appropriate products in
adequate supplies to use next year as needed, said Jardine.
Plant pathologists have screened all available commercial varieties of soybeans
for resistance to soybean rust, but none have proven to be resistant. There are
some varieties that are more susceptible to the disease and it will be important
to identify these early on to reduce the impact of the disease, said Jardine.
Growers that suspect that they may have soybean rust are encouraged to collect
samples and send them to their local state land grant university diagnostic labs
for evaluation. The diagnostic labs will be receiving additional soybean rust
identification training over the winter, said Jardine. A list of state land
grant universities is available at
www.apsnet.org/directories/extension/top.asp.
More information on soybean rust is available at
www.apsnet.org/online/feature/rust/
and additional information on soybean diseases can be found at
www.shopapspress.org/sore.html.
The American Phytopathological Society (APS) is a non-profit, professional
scientific organization. The research of the organization’s 5,000 worldwide
members advances the understanding of the science of plant pathology and its
application to plant health.
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Note to editors: To receive additional photos, please contact APS at
asteigman@scisoc.org or +1.651.994.3802.
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