August 16, 2012 - Field reports based on "Speed Scouting"
Wow, who would have thought that soybean aphid would be this insignificant. We have ended "speed scouting" of the fields we've been monitoring. Of the 18+ fields we have monitored since early July, 90% are R-5 or later. Only some June seeded fields are younger (R-4).
Spider mite activity has become less of a concern for multiple reasons. Growth stage of soybean are reaching R-6 quickly, if not already there. At the R 6.5 stage, soybeans would be considered safe from economic injury due to spider mite feeding.
The Minnesota Soybean Growers Association, Minnesota Soybean Research & Promotion Council, University of Minnesota Extension and your County Soybean Grower Associations (Becker/Mahnomen, Clay/Wilkin, Kittson, Marshall, Norman, Pennington/Red Lake, Polk & Roseau/Lake of the Woods) would like to invite you to this year’s northern Minnesota plot tours.
Bt corn with traits conferring resistance to corn rootworms offer growers a simple, seed-based solution to managing corn rootworms. These traits are far more effective than soil insecticides or seed treatments in protecting corn roots. Corn rootworms have developed resistance to many control tactics over the last 50 years including crop rotation, soil insecticides and foliar insecticides. Read more about corn rootworms in a four page fact sheet "Performance Problems with Bt-Rootworm Corn" written by Bruce Potter, IPM Specialist and Ken Ostlie, Extension Entomologist.
By David Nicolai, University of Minnesota Extension
ST. PAUL, Minn. (8/17/2012) —The drought and heat stress have taken their toll on kernel numbers in this year’s corn crop in many Minnesota counties through unsuccessful fertilization, aborted kernels, and decreased kernel size and weight.
During the last 2 weeks as drought conditions have intensified in some areas of the region and as soybeans are entering into a particularly stressful time of seed development, numerous odd potassium-like deficiency symptoms have developed.
In a YouTube video by a friend and colleague, Dr. Jim Camberato at Purdue, the video of soybean clearly shows upper leaves affected, which is totally against book descriptions. I think that much of the yellowing of upper leaves, starting at the leaf margins and moving into interveinal areas, eventually resulting in splotching and necrosis of parts of the leaves is potassium deficiency caused by drought conditions.
The link is www.youtube.com/watch?v=W3jRdftDLF8
Dave Franzen, Extension Soil Scientist, NDSU
by Jeff Stachler, U. of MN and NDSU Extension Agronomist – Sugarbeet / Weed Science
Glyphosate-resistant Kochia documented in Montana
Glyphosate-resistant Kochia Management in Wheat Stubble
Testing for Herbicide Resistant Kochia
View regional maps summarizing current observations in
Wheat and Barley