Join the University of Minnesota Extension Crops team in addressing all your crop-related questions this growing season, from soil fertility, agronomics, pest management and more. We will tackle issues as they arise to help you make better crop management decisions this season.
When Pests Bite Back
Dr. Tom Peters, Weed Scientist and Sugarbeet Agronomist with U of MN Extension and NDSU, discusses how irresponsible herbicide applications could backfire, and several pre-harvest strategies to prevent waterhemp escapes from replenishing the seedbank. Also, be sure to consider glyphosate-resistant volunteer corn when managing herbicide-resistant weeds. Bruce Potter, U of MN IPM specialist, discusses the status of soybean aphid populations, and the value of using the economic threshold. Other insects discussed include spider mites and corn rootworm.
Corn and soybean disease: Strategies for effective management in 2022
Dr. Dean Malvick, U of M Extension plant pathology specialist and crops program leader and professor of plant pathology discusses corn and soybean diseases he has observed and what might yet appear in 2022. Since it was first found in Minnesota in 2019, the fungal pathogen that causes tar spot in corn has spread from southeastern Minnesota to as far north and west as Stearns County in three growing seasons. Tar spot-related topics included scouting strategies and identification, when symptoms are likely to be observed, and what research has told us regarding proper active ingredient and application timing for managing tar spot with a foliar fungicide.
Getting ready for late-season insects
Dr. Robert Koch, U of M Soybean Extension Entomologist, and Bruce Potter, U of M Extension IPM Specialist discuss soybean and corn insects to keep an eye out for as we move into August. Soybean aphid populations have overall been low this year, but there are pockets of increasing population. Scouting is vital to determine where issues may be or if treatments aren’t needed. Other insects discussed include soybean gall midge, spider mites, and corn rootworm.
Corn pollination, atrazine herbicide use, and July insect updates
Dr. Jeff Coulter, U of M Extension Agronomist, updated us on the current status and outlook of corn pollination. Significant progress across much of the state should be occurring in the next week, though because of variable planting dates, it is difficult to generalize how upcoming hot weather will affect the overall crop across the state. Currently projected highs in the lower 90s should not cause significant pollination issues.Seth Dibblee, Environmental Scientist with the EPA, was on to discuss current news with atrazine. Atazine is a widely used post-emergence herbicide with about 33% of planted acres having an application in 2021. Currently, there are water quality concerns with atrazine that the EPA is proposing to address by adding restrictions to reduce runoff, such as disallowing use on saturated soil. A public comment period is open until Sept. 6, 2022 at: https://www.regulations.gov/search?filter=EPA-HQ-OPP-2013-0266. Dr. Anthony Hanson also gave a quick update on insects in early July. So far, soybean aphid hasn’t reached economic thresholds across much of the state, but populations are starting to increase in some areas. Whether it’s soybean aphid or other insects, be sure to check the insecticides are actually approved. Chlorpyrifos application , even if it’s in possession from a previous year, is no longer allowed for any agricultural use.
The latest regarding risks for and management of iron deficiency chlorosis (IDC) in soybeans
Drs. Dan Kaiser and Seth Naeve discussed iron deficiency chlorosis (IDC) in soybean on today’s episode. IDC is a result of the plant not being able to take up sufficient amounts of iron, which results in leaf yellowing with leaf veins remaining dark green. Kaiser and Naeve discussed soil conditions across the state that can result in IDC that result in high pH conditions that limit the availability of iron such as compaction and soil drainage.
Corn Rootworm Current Status, etc. and crop disease update/fungicides
The months of July and August typically brings new challenges for corn and soybean growers in
Minnesota. In this week’s episode, Bruce Potter, Extension Integrated Pest Management Specialist and
Andy Nesseth, part owner, Agronomist/Consultant from Extended Ag Services of Lakefield, MN provided
an update and reviewed management strategies for corn rootworm in Minnesota. Because of the
delayed spring planting season and resistant corn rootworm populations, Minnesota corn growers face
numerous field by field management situations for adequate corn rootworm control. Bruce and Andy
discussed the use of field traps and scouting as part of these management strategies along with
recommended crop and Bt hybrid rotations. The last portion of the program included Dr. Dean Malvick,
University of Minnesota Extension Plant Pathologist for corn and soybeans. Dean provided an update of
the biology and cultural control of corn tar spot, SDS (sudden death syndrome) in soybeans, white mold,
and frog eye leafspot in soybeans. Dean also reviewed the possible use of fungicides for some of these
diseases in terms of proper application timing.