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Michigan State University field crop agronomy update

EAST LANSING, MI. – Tuesday was the annual MSU Field Crop Agronomy update meeting for farmers and agribusiness persons in southeast Michigan.  Normally this meeting has been held at Cabela’s, but this year it was a virtual meeting held via zoom on a computer or smart phone.  And it was only a three-hour meeting instead of an all-day meeting which has had more information.

The first presentation was by Chris DiFonzo, Field Crop Entomologist, who reported on a relatively new insect for southeast Michigan, the Asiatic Garden Beetle.  Despite the word garden in the name, this insect pest can and has been devastating in some corn fields in Monroe County in recent years.  Her research into neonicotinoids class of insecticides has shown some early season vigor of corn with this treatment.  However, by fall harvest there was no yield difference between the treated and untreated corn. The use of neonics doesn’t affect some corn insect pests, including AGB.  And in corn planted into overwintering cover crops, one major potential pest is seedcorn maggot and not other early season grubs and larvae.

Marty Chilvers talked about loose smut and bunt (Dwarf and common bunt) diseases of winter wheat and potential harvest, yield and elevator dock problems with wheat infected with these diseases.  Grain harvested may have a fishy off-odor and shriveled kernels.  This disease overwinters in the soil so using wheat as a cover crop or infected seed may lead to crop problems in the future.  He then shifted to Tar Spot disease of corn, which is a relatively new disease in Monroe County and southeast Michigan.  His recommendation is to search out resistant varieties and scout fields at tasseling time, the R1 growth stage.  His research of fungicide use and timing has shown the best results when applied at the R4 growth stage, or even earlier at R3 or R2 in mid to late July.  Untreated corn could lose 50 bushels per acre, and treated corn could see a 25+ bushel increase if there is a heavy infestation.

Erin Burns talked extensively about Marestail (Horseweed), which can produce 200,000 seeds per plant and whose seeds can be windborne up to 300 miles.  This invasive weed is hardest to control in soybeans, so control in corn and wheat are recommended first.  She said planting into “clean” fields is a must, whether by tillage or herbicide, particularly as about 98 percent of this weed species is resistant to glyphosate.  Then a two-pass weed control program is needed, with residual herbicides for season long control as this weed has an unusually long germination period.  The new 2021 Weed Control Guide for Field Crops, MSU bulletin E-434 has four pages of recommendations, plus information about weed control when using cover crops.  The Weed Guide also has multiple tables for the MSU recommendations and new guidelines, and precautions, for LibertyLink GT27 soybeans, Enlist E3 soybean, Roundup Ready 2 Extend and XtendFlex soybean.

The Pigweed species of Waterhemp and Palmer Amaranth, which are also new and invasive weeds found in Monroe County and southeast Michigan, need special attention as they are herbicide resistant and need extra management for their control.  These weeds can be a problem in corn, soybeans or alfalfa so the Weed Control Guide has five entire pages of recommendations.  Persons interested in more information can always go to: for multiple factsheets and other weed control information.

Dennis Pennington has focused his wheat research report about row width and wheat seeding rate.  He has looked at wheat row spacings of 5 inches, 7 inches, 10 inches and 15 inches, partly as farmers are wondering if they can plant wheat with their soybean planter to save money and have more accurate seed placement and depth control.  So far he has not found any reason to support planting wheat into wider row spacings, such as 10 or 15 inches.  He is doing precision wheat placement and depth using multiple planters and drills and will continue that work into the 2021 season.  There is evidence that farmers are still overplanting wheat, with a recommended seeding rate of between 1million to 1.5 million seeds per acre.  The old “three bushels” per acre seeding rate needs to be put to rest and think about seeds per pound and seeds per acre, similar to how farmers think about corn and soybeans planting rates.  

Manni Singh is looking for farmers in southeast Michigan who would like to earn $200 to compare early planting of soybeans compared to a planting three weeks later than the first planting.  Bill Bierman got a check from MSU last fall for $200, though I don’t know if he framed it or spent it?  Farmers interested in this project can contact myself or Ricardo Costa Silva at the Lenawee County Extension Office for more information.