Des Moines, Iowa
June 9, 2008
If indications from fall trappings
in the Midwest are proven correct, growers may see minimal
soybean aphid pressure this growing season, according to soybean
experts at Pioneer Hi-Bred,
a DuPont business.
"Soybean aphids tend to be more prominent during odd years,"
says Leon Streit, Pioneer senior research scientist. "However,
although we are in an even-year growing season, Pioneer suggests
growers continue to monitor fields regularly. There still may be
areas that have a spike in soybean aphids."
Soybean aphids migrate in the fall to buckthorn, the
overwintering host. According to the U.S. Department of
Agriculture (USDA) integrated pest management Web site, suction
traps in fall 2007 recorded low numbers of winged soybean aphids
migrating. This indicates a year of low pressure.
While soybean aphid pressure may prove minimal this year,
Pioneer suggests growers continue to scout fields for any
indication of the pest. Aphids are small and yellow with
distinct black cornicles ("tailpipes"). At only one-sixteenth
inch long (the size of a pinhead or smaller), they cannot be
distinguished from other aphids with the naked eye. It is the
only aphid in North America known to extensively colonize in
soybean fields.
"Aphids have natural enemies that help reduce populations," says
John Soper, senior research director for Pioneer. "However, if a
grower has 250 aphids per soybean plant, an insecticide
treatment is recommended."
Additionally, growers can better determine the level of concern
for soybean aphids by reviewing the aphid-resistance rating of
the Pioneer® brand variety planted in each field. Pioneer
soybean varieties have ratings that indicate levels of
resistance relating to aphid reproduction and survival. Growers
can locate this information in a current seed catalog or by
contacting their Pioneer sales professional.
Based on ratings, growers should scout fields planted to
varieties with a below-average resistance rating first and with
greater frequency than fields planted to varieties with average,
above-average or exceptional resistance scores," says Streit.
According to screening and characterization studies, aphids will
reproduce faster on varieties with average or below-average
resistance ratings than on varieties with above-average or
exceptional resistance ratings.
If scouting results indicate a need for insecticide treatment
and a grower is unable to make applications immediately,
varieties with lower ratings should be prioritized for earliest
treatment with an insect control product such as DuPontTM Asana®
XL or Lannate® LV.
"It's important to note these ratings are relative comparisons.
Varieties with an exceptional resistance rating can come under
attack or be damaged by soybean aphids," says Streit. "But
varieties with exceptional ratings display much lower aphid
reproduction than those with average or below-average ratings."
To aid in monitoring this pest, a number of state university Web
sites and the USDA track the movement of aphids. Growers can
monitor sites such as
http://www.sbrusa.net (select soybean aphid in the upper
right-hand corner drop-down menu) and begin scouting when aphids
appear in their area.
Pioneer Hi-Bred, a DuPont business, is the world's leading
source of customized solutions for farmers, livestock producers
and grain and oilseed processors. With headquarters in Des
Moines, Iowa, Pioneer provides access to advanced plant genetics
in nearly 70 countries.
DuPont is a science-based products and services company. Founded
in 1802, DuPont puts science to work by creating sustainable
solutions essential to a better, safer, healthier life for
people everywhere. Operating in more than 70 countries, DuPont
offers a wide range of innovative products and services for
markets including agriculture and food; building and
construction; communications; and transportation.
® Registered trademarks of Pioneer Hi-Bred.
DuPontTM, Asana® and Lannate® are trademarks or registered
trademarks of DuPont or its affiliates. |
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