|
April 14, 2008
Source: Iowa State
University's Integrated Crop Management newsletter
by Daren Mueller, Extension Plant Pathologist
http://www.extension.iastate.edu/CropNews/2008/0408DMueller.htm
|
 |
|
A microscope is required to identify low-levels of
soybean rust on soybean leaves. |
In 2004, the Soybean Rust Fast Track System was put in place to
ensure rapid identification of soybean rust through First
Detectors and Triage Team Members. Over the past four years,
more than 700 individuals were trained as First Detectors or
Triage Members as part of the Iowa Soybean Rust Fast Track
System. While soybean rust did not infect fields in Iowa until
late 2007, we feel that the Fast Track System training helped
Iowa growers and agribusinesses through many of the unknowns
surrounding soybean rust.
One lesson learned while scouting for soybean rust in the
southern states and in confirming the first occurrences of
soybean rust in Iowa in 2007 is that the identification of the
disease in the field at low incidence (less than 10 percent of
leaves infected) and severity is very difficult. To identify
low levels of soybean rust, leaf samples must be incubated and
observed in the laboratory using a microscope, not observed for
lesions and pustules out in the field.
One of the main responsibilities of the First Detectors and
Triage Team Members was to filter out samples suspected of being
infected with soybean rust that were clearly infected with other
foliar diseases, not rust. However, because of the difficulty
identifying soybean rust in the field, the functioning of the
Fast Track System is being changed. First Detectors and Triage
Team Members will no longer be asked to filter out samples with
other soybean diseases.
The new role of First Detectors and Triage Team Members is to
serve as a conduit to get samples submitted properly to Iowa
State University. If soybean rust is suspected in a particular
field, samples should be submitted to the
Iowa State University Plant
and Insect Diagnostic Clinic even if tell-tale lesions and
pustules are not observed. We are in the process of writing a
new publication explaining how to submit a sample for early and
accurate diagnosis of soybean rust.
Daren Mueller is an extension specialist in the Department of
Plant Pathology.
This article was published
originally on 4/11/2008 The information contained within the
article may or may not be up to date depending on when you are
accessing the information. |
|
