By Scout Nelson
Dry weather conditions continue to affect weed management and crop production across South Dakota during the 2026 growing season. Limited rainfall and warm temperatures have accelerated spring planting progress, but the lack of moisture is creating challenges for herbicide performance in many crop fields. Producers are carefully monitoring fields as weeds continue emerging under drought conditions.
Eric Jones, Assistant Professor and South Dakota State University Extension Weed Management Specialist, along with Graig Reicks, Philip Rozeboom, Jill Alms, and David Vos, explains that preemergence herbicides require rainfall to move herbicide products into the soil profile where weed seeds germinate. Without enough rainfall, weeds may survive and emerge earlier, increasing the need for postemergence applications of herbicides to protect crop growth.
Specialists explain that drought-stressed weeds are more difficult to control because they reduce growth and photosynthesis during dry weather. Reduced transpiration and thicker leaf cuticles can limit herbicide absorption, making herbicide applications less effective. Weeds that are not actively growing may not absorb enough herbicide for complete control.
Environmental conditions also play an important role in herbicide activity. Higher humidity levels during morning and evening hours may improve herbicide absorption, but producers should use caution because temperature inversions may increase spray drift risks. High temperatures and low humidity may also increase herbicide evaporation and reduce effectiveness. Producers are encouraged to carefully review herbicide labels and monitor weather conditions before applications.
Experts recommend applying herbicides when weeds remain small, generally two inches or less, because smaller weeds are easier to control. Increased spray output may improve herbicide coverage and increase the amount of active ingredient reaching weed surfaces. Humectants may also help slow droplet evaporation and improve herbicide contact time on leaf surfaces during dry weather.
Successful weed control during drought depends on timely scouting, proper spray timing, adequate coverage, and careful environmental monitoring. These weed management practices support crop protection in row crops, pastures, and rangeland areas experiencing ongoing dry weather conditions.
Photo Credit: gettyimages-zoomtravels
Categories: South Dakota, Crops, Weather