Urbana, Illinois
August 2, 2005
A spore trap in Champaign County, Illinois has
turned up 4 rust-like spores, but plant pathologists are quick
to say that this finding does NOT mean we have Asian soybean
rust infection in Illinois.
"No infected plants have been found and the spores are the shape
of fungal rust spores but they have not yet been identified as
Asian soybean rust," said Suzanne Bissonnette,
University of Illinois (U of
I) Extension Educator IPM.
She says cooperators in Illinois have been monitoring spore
traps and monitoring sentinel field plots through out the 2005
growing season. The purpose of the monitoring has been to assist
growers in the state to make economic and environmentally sound
soybean rust management decisions and to serve as a pre-warning
to increase infield soybean scouting from a weekly schedule to a
three-day day schedule in vulnerable areas.
"The word 'rust' refers to a huge family of fungi that infect
plants. There are many hundreds of species of rust that infect
green plants. For example we have fungal rust species that
infect corn and some that infect wheat and some that infect
hollyhocks and the list goes on and on," said Bissonnette.
"Fungi in the rust family have numerous microscopic features
that look similar and thus they are organized into the rust
family for purposes of identification by a mycologist or plant
pathologist."
Throughout the state, plant pathologists have been sampling the
air for Asian soybean rust spores using windsock spore traps.
And although rust-like spores were found last week using a
microscopic examination, it doesn't mean that those spores are
Asian soybean rust.
At this time, Bissonnette says that U of I Extension
recommendations are that farmers south of Champaign County in
Illinois and within a 200 mile radius begin diligent scouting
for Asian soybean rust on a three day schedule.
"Check the lower half of 20 plants in 5 locations in a
contiguous field. Suspicious samples consisting of 20 leaflets
wrapped in a paper towel should be double bagged in zip locked
bags and brought to your local Extension Unit office for
pre-evaluation by diagnosticians to determine if further testing
at the U of I Plant Clinic is necessary.
"Our recommendation at this time is NOT to spray fungicides for
Asian soybean rust, no infection has been found," said
Bissonnette.
The official UDSA soybean rust reporting website is at
www.sbrusa.net and has
reported the detection of 'rust-like' spores in a number of
states to the south of Illinois such as Tennessee and Kentucky,
and both have yet to find
infection. Asian soybean rust plant infection has only been
detected this season in Florida, Alabama, Mississippi and
Georgia.
"So don't over react to the spore findings in Illinois. But it
would still be wise to redouble your soybean scouting efforts.
You will save yourself time, money and will be a continuing good
steward to the land by getting the right information before
reacting" said Bissonnette. |