Want your herbicide applications to be as effective as possible? Here are a few tips.
- Know the weeds you are trying to control. Armed with the knowledge of what weeds are most problematic, you can use weed response tables and weed control guides, available through universities and companies, to make the best decisions.
- For post-emergence herbicides, scout your fields. “For most farmers, walking over the fields and noting the weeds present is probably good enough, but scouting from the pickup truck won’t do it,” says Alan York, Ph.D., professor of crop science at North Carolina State University.
- Apply post-emergence herbicides at the proper time. “Few farmers spray too early. Treating weeds when they are smaller and easier to kill can prevent early season competition with crops and has ramifications for resistance management,” says York. “You should start scouting fields no later than 14 days after planting. The weeds may not be ready to treat that early, but early scouting can prevent having to catch up later.”
Time of day can also impact how well herbicides work. For example, some weeds have leaves that fold up during the low light conditions, making coverage challenging.
Check the label requirements for statements that say there could be reduced activity for the herbicide late in the day or in the early morning.
- Follow label requirements to make sure you use the proper application techniques. York notes having the sprayer calibrated, applying the right volume per acre and using suitable nozzles are important. Following label instructions is probably the most important thing you can do to make sure the herbicides work as well as they can.
- Monitor the weather. Farmers should manage herbicide use taking into account the impact of weather on efficacy. For example, soil-applied herbicides require rainfall to activate, but too much rainfall will dilute it or wash it away.
Herbicides are a significant investment and an important tool. Follow label instructions to help herbicides be effective.