cropCENTRAL | Field Crop Production Resources

One of the most daunting challenges facing agronomic crop production is the continuing evolution of weeds resistant to herbicides. The magnitude of herbicide resistance is best measured on a global scale. The most recent summary indicates 520 unique cases of herbicide resistance—encompassing 268 species—occur globally. Approximately 11–12 cases of unique resistance are discovered each year. In contrast, our understanding of how and why weeds are evolving various resistance mechanisms is evolving much slower. This introduces a somewhat precarious situation: if we do not fully understand how/why these resistance mechanisms evolve,…

Dry soil conditions across many areas of Illinois have contributed to accelerated crop planting. It is a bit unusual at this point in the season that such a high percentage of corn and soybean acres already have been planted. Soon, postemergence herbicide applications will begin. However, one potentially adverse consequence of very dry soil is the often large amount of dust propelled into the air by either application equipment or high winds.
Airborne dust has been shown to reduce the activity of some foliar-applied herbicides,…

While conditions during much of April were conducive for planting, these same conditions were NOT conducive for good performance of soil-residual herbicides. Many surface-applied herbicides received neither timely precipitation nor mechanical incorporation to move the applied herbicide into the soil solution. Herbicide effectiveness can be significantly reduced when a soil-applied herbicide is sprayed on a dry soil surface with no incorporation (mechanical or by precipitation) for several days following application. The amount of precipitation required to move the herbicide into the soil and how soon after application the precipitation is needed are difficult to define and can vary by herbicide,…

Soil-residual herbicides are important components of integrated weed management programs.  Reducing the number of weeds exposed to foliar-applied herbicides helps reduce the selection intensity for weeds to evolve resistance to foliar-applied herbicides. Residual herbicides applied with postemergence soybean herbicides also can reduce the need for a second postemergence application. However, simply applying a soil-residual herbicide does not guarantee the product will provide the desired level or duration of weed control. Many edaphic and environmental factors influence the level of weed control achieved by soil-residual herbicides.…