Iowa Farmer Today
05-26-07
USDA investigators examine how, why Asian soybean rust was reported in Iowa
By Tim Hoskins, Iowa Farmer Today
Scientists studying Asian soybean rust found on a South Central Iowa farm have
turned over the investigation to the USDA because only one leaf was heavily
infected but no others.
Greg Tylka, Iowa State University plant pathologist, says investigators found
no other evidence of soybean rust.
Rust was not found in the sample on any other plant leaves left in the suspected
field or on the stems or beans submitted in the sample or in the bin where the
sample was reportedly taken from the Mahaska County farm.
While several questions remain, it seems the only thing known is a bean leaf with
Asian rust arrived at Iowa State University’s Plant Disease Clinic on March 8.
On March 12, the USDA confirmed the sample had soybean rust.
On March 13, personnel from the Iowa Department of Agriculture and Iowa State
University collected additional samples of seed and plant materials from bins at
the South Central farm where the sample was allegedly collected.
“We looked and looked and found nothing,” says Tylka about the trip to the fields
and farm in Mahaska County.
Scientists did find frogeye leafspot on samples from the field.
“We did verify that one leaf submitted in a plant sample was infected with Asian
soybean rust, but how it got into Iowa still needs to be determined,” Bill Northey,
Iowa Secretary of Agriculture, said in a news release.
“After careful examination of the materials collected to date, we believe no Asian
soybean rust infection occurred during the 2006 growing season in Iowa.”
That leaves the case with a bunch of unanswered questions.
For answers to those questions, an investigation is being conducted by the
USDA’s Inspector General’s Office.
Robin Pruisner, Iowa Department of Agriculture entomology and plant science
bureau chief, says there are potential legal ramifications from this case.
She says a “heavily” infested soybean leaf submitted months after the soybean
crop was been harvested in Iowa raised questions.
Pruisner says farmers should not let this case hinder them from calling for help if
they have something wrong in their soybean fields.
However, she says if a farmer has problem during the growing season,
investigators are able to travel to the field while the crop is still in the field to
determine the cause.
She says the investigation continues because they want to present the best
information to farmers and verify the soybean rust modeling systems are
working.
If there was a case of soybean rust in 2006, it would have meant the modeling
systems were not working correctly.
Tylka says news of the soybean rust case should not divert farmers from the
threat of soybean rust in the 2007 growing season.
When the rust sample was confirmed, officials stressed the discovery from the
2006 growing season had little effect on the chances of rust becoming a threat in
2007 because a freeze kills it.
Tylka says that advice still holds true.
Farmers should pay attention to what is going in the South.
Currently, soybean rust has been found in a kudzu patch west of New Orleans.
That is as far west as it has been found this year and is 53 days ahead of last
year’s first find in Louisiana.
Six counties in Florida have soybean rust. No rust has been found in Alabama,
Georgia or Texas.