SEVERAL WEED SPECIES ARE DEVELOPING STRONGER WIDESPREAD resistance to glyphosate in the American Crystal Sugar Company growing area. Waterhemp problems are no longer uncommon in Cass, Clay, Wilkin and Richland counties. Waterhemp resistance is suspected north of these counties as well. Common ragweed resistance is present in most of the Red River Valley to date. Some isolated problems with suspected Kochia resistance occurred in 2013. The previous Ag Notes #586, January 23, 2014, discussed options for glyphosate resistant weed management in corn and soybeans. This issue discusses proactive strategies to use for sugarbeet fields.

Management Strategies - Waterhemp

Soil Applied:

1. Apply ethofumesate at 3-5 pt./A + metoachlar (Dual) at 0.5-1 pt./A. Lower rates reduce crop injury while higher rates improve control. Lower cost than option
2. Apply ethofumesate at 6-7.5 pt./A. Higher cost but reduced crop injury risk.

Post-emergence:

1. Always spray very small weeds, < 1".
2. Always use AMS + HSMOC or NIS.
3. Adding 4-6 oz./A. ethofumesate to glyphosate will almost always improve control.
4. Use highest allowable glyphosate rates in all three applications.
5. Cultivate if necessary to control escaped weeds.
6. Use hand labor to achieve weed free fields if necessary.

Common or Giant Ragweed Strategies

Post-emergence:

1. Use maximum glyphosate rates in all applications.
2. Use 3-4 oz. of Stinger per acre in each glyphosate application.
3. Spray small weeds < 1" tall.
4. Use cultivation and/or hand labor to maintain weed free fields.
5. Don't exceed 10.5 oz./A of Stinger per season.

Kochia Strategies

Soil Applied:

1. Apply to 6 to 7.5 pt./A. of ethofumesate. Higher rates for heavy soils and severe weed pressure.

Post Applied:

1. Apply maximum glyphosate rates + ethofumesate at 4-6 oz./A plus HSMOC at 1.5 pt./A or NIS (0.25% V/V) + AMS to ? 1" weeds.
2. Add Betamix or generic Betamix at 12 to 24 oz./A. to dime size Kochia and repeat as necessary.
3. Upbeet may be added to POST application tank mixes if the Kochia is not ALS resistant to give added benefit.

American Crystal Grower Seminar Program Topics and Speakers