Manhattan, Kansas
September 11, 2007
Wheat seed quality and planting
issues remain a concern for many growers in Kansas this year,
according to two Kansas State
University scientists.
Test weight, germination scores, seedbed conditions, and
seed-borne diseases are factors that need to be considered this
fall, said Jim Shroyer, who is the agronomy state leader for
K-State Research and Extension.
Some of these potential problems can be addressed with fungicide
seed treatments, according to Erick De Wolf, K-State Research
and Extension plant pathologist. The relative usefulness of
fungicide seed treatments will depend on the situation.
"We continue to hear concerns about using low-test-weight seed,"
De Wolf said. "If seed has a test weight of 55 pounds per bushel
or less, but no evident disease problem (scab, black point,
loose smut, or common bunt), will a fungicide seed treatment be
of any benefit? This is a hard question to answer, but it is
possible that a fungicide seed treatment can improve or protect
seedling vigor under stressful conditions. With the relatively
good price of wheat, a fungicide seed treatment is probably a
good investment on low-test-weight seed."
Some areas of the state are reporting higher-than-normal levels
of seed affected by head scab and black point, De Wolf said.
These diseases can reduce germination rates. In many years,
fungicide seed treatments result in small differences in
germination and stand establishment. However, these products can
have a greater impact in
years when head scab and black point are affecting the seed
quality.
If seed has a low test weight or is infected with scab, the
first step should be to have it cleaned hard to remove the
lightest and poorest quality seeds, Shroyer said. Once the seed
lot has been cleaned, the seed should be tested for germination.
"If the germination is still lower than desired, you will
probably want to adjust the seeding rate to make sure you hit
your target plant population and may also consider fungicide
seed treatment to help improve germination," the agronomist
said.
The typical response to a fungicide seed treatment on seed that
is badly damaged by scab would be about an 8 to 10 percent
improvement in germination, De Wolf said. This level of response
makes seed lots with a germination rate of around 80 to 90
percent a strong candidate for a seed treatment. The case is
even stronger if the seed lot still contains kernels with signs
of scab.
There are a number of good seed treatments available to growers,
including Raxil MD, Dividend Extreme, and Charter, De Wolf
added.
"Some results suggest that combing a broad-spectrum fungicide
product like Dividend Extreme with a second fungicide, Maxim
4FS, can further improve the efficacy of the seed treatment in
scabby seed lots," he said. "The cost of these products should
range from about $1.30 to $1.75 per bushel, depending on the
combination of active ingredients and rate. It is best to use
the full rate of these products when attempting to control the
Fusarium fungus that is present in the scabby seed."
More information on wheat seed treatments is available at county
or district K-State Research and Extension offices or on the
K-State Department of Plant Pathology Fact Sheet "Wheat Seed
Treatments"at:
http://www.plantpath.ksu.edu/DesktopDefault.aspx?tabid=536.
Brand names appearing in this article are for product
identification purposes only. No endorsement is intended, nor is
criticism implied of similar products not mentioned.
K-State Research and Extension is a short name for the Kansas
State University Agricultural Experiment Station and Cooperative
Extension Service, a program designed to generate and distribute
useful knowledge for the well-being of Kansans. Supported by
county, state, federal and private funds, the program has county
Extension offices, experiment fields, area Extension offices and
regional research centers statewide. Its headquarters is on the
K-State campus, Manhattan. |
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