Fayetteville, Arkansas
January 19, 2005
Some 30,000 acres of Arkansas
soybeans had to be replanted in 2004 because of fungal seedling
diseases, according to best estimates, said Dr. Chris Tingle,
soybean specialist for the
University of Arkansas Division of Agriculture.
“Each year, growers are trying to plant earlier,” Tingle said.
“With Arkansas’ climate, such early crops face the potential for
cool, rainy weather that stimulates seed diseases.”
Ongoing Division of Agriculture research is showing the
effectiveness of using broad-spectrum fungicide seed treatments
as a line of defense against soil borne pathogens like
Pythium that attack soybean seed. Plant pathologist Dr. John
Rupe is also studying the use of varying planting methods to
improve disease management.
In research supported by the Arkansas Soybean Promotion Board,
Rupe, Tingle and plant pathologists Dr. Rick Cartwright and Dr.
Craig Rothrock are determining whether raised seedbeds offer
advantages.
In test plots at research and extension centers, treated and
untreated soybean seed has been planted on both raised beds and
conventional fields at varying row widths and planting dates.
Rupe said both high- and low-quality seed are used with
planters, drills and broadcast.
In the first year of a three-year study, Rupe said raised beds
are showing promise.
“The advantage of raised beds is that they get the seeds above
water in wet planting seasons,” he said. “Also, the beds are
warmer, which helps provide better emergence than planting in
flat ground, especially in early-planted soybeans.”
He also saw some differences in the type of equipment used for
planting.
“The fields seeded with a planter had better stand counts than
those where a drill or broadcast were used, because the planter
provided better soil contact,” he said.
Rupe is also looking at nine different seed treatments used with
high- and low-quality seed at three planting dates (April, May,
June) and at three locations (Keiser, Stuttgart and Hope). “Four
of these treatments showed significant differences in
effectiveness in initial tests,” he said.
With rising costs of seed, fuel and other inputs, replanting
fields because of losses from seed diseases has a big economic
impact on the state and makes the Division of Agriculture
research critically important to growers, Tingle said.
“The key for Arkansas producers is to determine the most
productive method and what reduces risk of diseases,” he said.
Rupe is also researching cultivar resistance to fungal diseases.
“Originally, resistance was found in Archer, a Group I cultivar
that is not adapted to Arkansas,” he said. “Now we’re looking at
four commercial varieties adapted to Arkansas, two of which
appear to have resistance. We’re testing them with and without a
Pythium fungicide.”
Seed treatments have limited effectiveness and wear off with
time, he said. Natural resistance is always there.
“We want to see if we can identify resistance and see how
effective it is,” Rupe said. “We will take these to yield and
see how they perform.” |