Preharvest Weed Control in Small Grain

NDSU Extension Service
HTML Editors: Dr. Jochum Wiersma & Tracy Allrich

These late-season applications are intended to facilitate harvest and reduce clean-out and dockage losses. Performance varies; results are best if weeds are not stressed or approaching maturation. Follow application to harvest intervals. Take special note of risk of drift to adjacent crops - many are highly sensitive to some herbicides and the relatively high rates used on large acreages presents a greater risk.

2,4-D

Labeling on several products include preharvest application on wheat, barley, and oats after dough stage. Early application prior to joints loosing green color is discouraged. Ester provides more rapid burndown. Rates for most situations are .75 to 1 lb./A act. Performance on sunflower, lambsquarters, and mustard is good; it is useful for Canada thistle seed suppression. Do not use straw for feed.

Banvel + 2,4-D

A tank-mix of 1/2 pt Banvel (4 L) plus 1/2 to 1 lb./A a.e. 2,4-D amine or ester was labeled during 1992 as a special 24 (c) for use on wheat. Extension for 1993 is anticipated, pending final approval. A 14-day minimum application to harvest interval is required. Apply at hard dough after green color is gone from the nodes. Not for use on seed fields unless a germination test shows acceptable (95 % +) germination. Useful for kochia, pigweed, Russian thistle and others. Minimum carrier is 3 gpa for air. Do not graze or feed fodder.

Roundup RT and Landmaster BW

Apply after hard dough stage and at least 7 days before harvest. Rates are 1 to 2 pt/A Roundup or up to 84 ounces of Landmaster BW. Roundup may be tank-mixed with 1/2 to 1 lb./A 2,4-D. Add surfactant with Roundup. Especially useful to control foxtail; also provides suppression of field bindweed and Canada thistle. Use minimum of 3 gpa carrier. Not recommended for seed fields; germination or immature seed may be reduce. Do not permit dairy or meat animals being finished for slaughter to graze treated fields for two weeks after treatment.

Minnesota Association of Wheat Growers

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