cropCENTRAL | Field Crop Production Resources

The continual evolution of weed species and populations resistant to herbicides from one or more mechanism-of-action families represents one of the most daunting challenges faced by weed management practitioners.  Currently in Illinois, biotypes of 12 weed species have been confirmed resistant to one or more herbicide mechanisms of action.  Resistance to herbicides that inhibit the ALS enzyme is the most common type of resistance in Illinois.  Waterhemp has evolved resistance to more herbicide mechanisms of action than any other Illinois weed species,…

Dicamba is a growth regulator herbicide that can be used to control existing weed vegetation prior to crop planting.   Several commercially-available products contain dicamba, but not all products are specifically labeled for application prior to crop (especially soybean) planting.  Clarity may be applied before planting no-tillage corn at rates ranging from 8 (on coarse soils or medium- and fine-textured soils with less than 2.5% organic matter) to 16 (medium- and fine-textured soils containing 2.5% or greater organic matter) fluid ounces. …

Ideally, soil-residual herbicides should provide several weeks of weed control but not persist long enough in the soil environment to cause damage to rotational crops.  Dry soil conditions, similar to what most of Illinois experienced during the 2012 growing season, often slow the rate of herbicide degradation and increase the potential for damage to rotational crops from herbicide carryover.  Some remember the dry growing season of 1998 and the problems encountered in 1989 due to the persistence of one or more soil-residual herbicides that did not adequately degrade in the dry soil conditions of 1988. …