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Weed Control, Status Report, Week of May 15, 2022 (05/19/22)

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Producers in northeast North Dakota and northwest Minnesota are in an interesting place. Weeds are beginning to emerge in fields but fields are muddy below the soil surface making tillage to remove weeds a compromise between a clean start, clean seedbed vs. perhaps compromising the seed bed at plant. In addition, wheat, corn, and sugarbeet will be emerging at the same time as broadleaf weeds. What to do?

I try not to compromise the seedbed as we normally have to live with the mistakes we make at plant for the entire season. I would consider vertical tillage or use of a multi-seeder and consider burndown herbicides to control emerged broadleaf weeds. Paraquat makes a lot of sense for me now. Consider my logic path:

•     Paraquat is a contact herbicide so complete coverage of foliage is essential to maximize control of weeds. Spray nozzles producing medium to coarse droplets are recommended. Consider greater than 10 gpa carrier to facilitate good coverage.

•     Mixing order is important with paraquat alone or in mixtures. Fill spray tank 1/2 full with carrier.  Add non-ionic surfactant to tank and begin tank agitation and continue throughout mixing and spraying. Add co-herbicides; dry formulations (WP, DF) first followed by liquid formulations (SC, EC, L). Finally, add paraquat and fill remainder of spray tank.

•     Adjuvant is key with paraquat products. I suggest NIS but the label also suggests methylated seed or crop oil concentrate.

•     Paraquat has good tank mix compatibility with many products

•     Apply paraquat at 0.375 lb/A. There are many paraquat products. Use the appropriate rate depending on formulation.

Paraquat products are dangerous products and must be used with careful paranoia. Mixers, loaders and applicators need to dress properly including long-sleeve shirt and pant, protective eyewear, gloves, and a NIOSH-approved particulate respirator. Or consider asking your ag-retailer to make the application.

One other key decision is incorporating your soil residual herbicide into soil. Use of paraquat probably locks you into a PRE program. However, I am asking sugarbeet growers to shallow incorporate sugarbeet residuals preplant to ensure they will immediately control emerging weeds.

 

Tom Peters

 Extension Sugarbeet Agronomist

NDSU & U of MN