Farm Horizons
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June 6, 2016
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Page 7
Managing crop pests
Each year, it seems we get just the right
ment practice. This gives crop producers
weather conditions for a pest, insect, or
time to identify and monitor pests before
Dave Schwartz they exceed economic thresholds.
disease, and the population of that pest
Certified crop advisor
explodes.
Over the years, I have been called
Gold Country Seed
Last year, cooler, damp weather in
out on many crop pest problems, and
July triggered white mold infection in
oftentimes, the damage had already
soybeans. Hot, dry summers are ideal
been done, so it was too late to justify
for spider mites that feed on many types
any type of rescue treatment. Economic
of plants.
thresholds are based on sound research, so growers know
So, what can we expect for the 2016 growing season? how much crop damage can occur before action needs to
It all depends on weather. We have had a nearly ideal be taken.
spring for planting, with very little soil compaction, so
A couple of diseases to watch for on continuous corn
I would expect to see less phytopthora root rot in soy- acres are Goss’s Wilt and Northern Leaf Blight. Goss’s
beans.
Wilt was first identified in the state five to 10 years ago in
It seems like we have experienced less strong southerly western Minnesota in a corn field under irrigation. Since
winds this spring, so potato leafhoppers, which blow in then, it has spread across the state all the way into northfrom southern states, are less likely to be a problem in the west Minnesota. It does not survive well in corn/soybean
first cutting of alfalfa.
rotations, so is nearly always found in continuous corn.
Some weather forecasts are predicting a warm, dry AuI’ve noticed more northern leaf blight the past two
gust, so this may reduce the potential for diseases, but years. The fungus produces cigar-shaped lesions on lower
create a more favorable environment for spider mites in leaves of plants. It’s a good idea to rotate out of corn when
soybeans.
either of these diseases is identified. n
Scouting fields on a regular basis is a good manage-