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Plan to Spray Weeds Once Sugarbeet Fields Dry (05/21/15)

I suspect everyone benefited from last week’s precipitation. The rainfall was crucial for early season growth and development but has prevented us from working in the field for up to fourteen days in some locations.

Plan to Spray Weeds Once Sugarbeet Fields Dry

I suspect everyone benefited from last week’s precipitation. The rainfall was crucial for early season growth and development but has prevented us from working in the field for up to fourteen days in some locations. In the meantime, weeds have continued to grow. The lambsquarters is a little taller and redroot pigweed cotyledons have appeared in fields. I have not heard or confirmed waterhemp emergence. However, I can assure you, it will not be far behind.

It’s time to spray for weeds. Farmers may consider a tank mixture of postemergence and residual herbicides using a concept we call ‘lay-by’. I recommend glyphosate at 0.98 lb ae/acre plus non-ionic surfactant and ammonium sulfate to eliminate all emerged weeds. Use a tank-mix application with glyphosate such as Nortron, Betamix, Stinger or UpBeet if there are tough-to-control weeds in the field such as lambsquaters, kochia, common ragweed or giant ragweed.

I also recommend adding one of the chloroacetamide herbicides to the tank-mixture for soil residual control. There are several choices including metolachlor (Dual Magnum, Cinch or a generic), Warrant or Outlook. The herbicide you choose is up to you; I have achieved good results in my program with all of them. The rate one chooses will be dependent on several factors including: 1) growth stage of sugarbeet; and 2) was ethofumesate or metolachlor applied preemergence? I recommend split rates if no residuals were applied and the beets are cotyledon to two leaf stage. I recommend labeled rates if there was preemergence application or sugarbeets are 4 leaves or greater.

I am forecasting waterhemp by June 10th in the south and June 15th in the north of ‘waterhemp country’. The idea is to get your residual herbicides applied and activated before waterhemp emerges.

Tom Peters

Extension Sugarbeet Agronomist

NDSU & U of MN

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