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Syndrome (SDS). After visiting the field and making more
observations, SDS was confirmed. This is the first
report of SDS in Nebraska; however, its arrival is not a
surprise as Missouri and Iowa both have it.
Sudden Death Syndrome (SDS) of soybean is caused by the
fungus Fusarium solani f. sp. glycines. This is a
different fungus than the one that causes early season
damping off problems associated with soybean stand. This
year’s weather pattern, with both early season moisture
and moisture at the early reproductive stages, is
conducive to the development of SDS. Now is the time
that you should see the full symptom expression of this
disease.
SDS
is favored by high yield environments. Soil compaction
and high fertility levels have also been associated with
increased levels of SDS. The foliar symptoms start with
interveinal necrosis and the spots coalesce to form
brown streaks between the leaf veins with yellow
margins. Leaves eventually drop with the petiole (leaf
stem) remaining attached. The root system will have a
deteriorated tap-root and lateral roots will only be
evident in the upper soil profile. The root cortex is
light-gray to brown and may extend up the stem.
Typically, plants can be easily pulled from the ground
and a dark blue fungal growth will be visible on the
roots. The blue color will not be evident in dry soil
conditions.
Last
week at a field day near Nemaha a local soybean grower
brought a plant with symptoms of Sudden Death
At
this time SDS does not appear to be a widespread problem
in Nebraska and is most likely only going to be found in
river bottom areas. It you have a field which is
exhibiting symptoms of SDS, please contact us
(402-472-8723;
lgiesler1@unl.edu) so we can confirm it and get a
better idea of how prevalent this disease is.
Loren J. Giesler
Extension Plant Pathologist |
