Herbicides are welcomed by many farmers and backyard gardeners because of their potential to eliminate much of the need for long hours of manual weed control practices. When used properly, herbicides can control a variety of unwanted weeds with little to no effort; however, when used improperly, they can cause injury and contamination. To avoid an unwanted scenario, it’s best to follow the recommended practices for herbicide use.
Follow label directions: Use herbicides only when necessary, only at recommended rates and time of application, and only for those crops and uses listed on the label. Also, be familiar with current laws and regulations regarding herbicide usage or license requirements. Remember that the label is the law and it should be viewed as such.
Clean contaminated equipment: Sprayer cleanout is essential to prevent crop injury from spray contamination and to also preserve the life of the sprayer. Flush tanks, lines, booms and nozzles for at least five minutes with fresh, clean water. Add a cleaning solution and pay special attention to crevices and plumbing fixtures. Flush the lines once more with fresh water.
Mix tank in an appropriate place: Avoid mixing near wells and never leave a sprayer unattended while filling. Groundwater can be contaminated if there are spills or back-siphoning into the well. If possible, fill sprayers at least 50 feet from a well. If this cannot be achieved, an antiback-siphoning device should be installed on the hose. In addition, rinse sprayers at the field site, rather than near any wells.
Calculate and calibrate accurately: Carefully calibrate the sprayer at the beginning of the spraying season, and then re-check periodically. Too little or too much herbicide concentration will not yield the desired weed killing affects. Also, be sure to calculate and mix the right amount. This will avoid excess or running short of herbicide while in the field.
Be aware of drift: Drift occurs when spray droplets or dust particles are carried by air movement from the application area to an unintended area. Vapor drift takes place after application. The herbicide evaporates, or volatizes, and produces a gas that is carried by wind currents onto the soil or plants of an untreated area. If possible, do not apply herbicides when the wind speed is greater than 10 mph. If wind speed or direction changes during an application, immediately adjust the buffer size or location, or stop the application.
Be a soil conservationist: Runoff from fields is a common contributor to surface water contamination. Good soil conservation practices will reduce erosion, and therefore decrease herbicide and nutrient runoff.
Learn to identify herbicide injury: There are many factors that can cause the symptoms often attributed to herbicide injury. When evaluating crops, first look for patterns of plant injury or uncontrolled weeds. Also, learn the history of the problem area and recall the weather conditions at and immediately following the herbicide application.
Herbicides can be a great tool to combat problem weedy areas. In order that they are used and as effective as intended, always follow label directions. Once again, remember that the label is the law so carefully read and follow all precautions.