Wet fields made spring weed control difficult to impossible in many winter wheat fields, and prolonged wet conditions have encouraged prolific weed growth from large competitive broadleaf weeds like giant ragweed and lambsquarters. As we approach harvest in southern WI (week of August 21st) growers simply have limited herbicide options for preharvest weed management:
1. 2,4-D products. There is a 7 day pre-harvest interval with this product. The downside of 2,4-D is you are NOT allowed to feed treated straw to animals. That restriction alone probably leaves just one option….
2. Glyphosate products. There is also a 7 day pre-harvest interval with this product, and it can NOT be applied until the grain is at the hard dough stage (30% moisture or less). Grain treated with glyphosate at this growth stage should not be used for seed as germination can be significantly lowered.