Blacksburg,
Virginia
August 22, 2005
Virginia
Tech scientists say that there has been a change in the
status of the fungus causing Asian Soybean Rust but that the new
information is still too preliminary for any action on the part
of the Commonwealth's soybean producers.
A single cluster of six
urediniospores found at Virginia Tech's Tidewater Agricultural
Research and Extension Center in Suffolk was identified by
morphological characteristics as matching the description of the
fungus.
"The
spores in question appear to resemble the causal agent of Asian
Soybean Rust, Phakopsora pachyrhizi, said Erik Stromberg,
interim head of the Department of Plant Pathology, Physiology
and Weed Science in Virginia Tech's College of Agriculture and
Life Sciences. "But we can not be absolutely certain that they
are. The weather conditions between Aug. 5 and 11, the time the
sample was found, were extremely hot and dry and not conducive
for promoting the infection process. Researchers found no
indication of Asian Soybean Rust when they examined the adjacent
sentinel plots and other nearby fields. At this time, no
recommendation for fungicide is warranted in Virginia. It is
highly unlikely that Asian Soybean Rust will be detected in any
soybeans in Virginia for at least three weeks."
The presence of spores does not
mean the infection is present. It means that the scouting for
the disease will be intensified until the crop progresses
through the most vulnerable stages from beginning pod fill up to
full seed.
Farmers suspecting the presence
of soybean rust in a field should contact the local Virginia
Cooperative Extension office for help in confirming its
identity. Virginia Tech has an intensive ongoing program for
detection of the disease and warning growers of the need to
apply fungicide sprays for disease control. Reports on the
status of disease and field scouting are posted twice weekly on
the website and there are recorded updates at 1-804-657-6450
ext. 103. More information on Asian Soybean Rust can be found at
http://www.ppws.vt.edu/ipm/soybeanrust/index.htm.
Soybean's farm gate value in
Virginia has ranged from $75 million to $100 million annually.
The early warning provided by the scouting system will permit
growers to act only when necessary. The primary tool for growers
is the use of fungicides, which are costly and will not be
effective if applied too early or too late. Research continues
on finding resistant varieties. |