Proper Sprayer Cleaning Prevents Herbicide Damage to Crops

By Blake Jackson

Penn State Extension is reminding growers that thoroughly cleaning spray equipment is one of the most important steps in protecting crops during the growing season.

According to Extension educators Tosh Rung Mazzone and Stephen Campbell, Pennsylvania farmers have experienced a wide range of weather conditions this year, from excessive rainfall and flooding in the western and northern regions to prolonged heat and dry conditions in the south-central and southeastern parts of the state.

As crops continue to develop and planting wraps up, many producers are shifting their attention to applying herbicides, fungicides, and insecticides. Because application windows are often limited by weather, it can be tempting to rush the process.

However, failing to properly clean sprayers between applications can result in herbicide residues damaging sensitive crops.

Even trace amounts of herbicides remaining inside tanks, hoses, filters, nozzles, or booms can cause serious crop injury.

Modern herbicides are frequently applied at very low rates, making even small residues capable of producing visible symptoms such as leaf cupping and plant distortion in susceptible crops. A simple rinse in the field is often not enough to remove these residues completely.

Sprayer cleanout is equally important before fungicide applications. While fungicides generally do not injure crops the way herbicides can, they are often combined with insecticides, biological products, foliar fertilizers, and adjuvants. These mixtures may loosen herbicide residues left inside the sprayer, increasing the risk of crop damage during subsequent applications.

Extension specialists recommend following every product label carefully, as cleaning instructions vary by pesticide.

Applicators should completely drain the sprayer immediately after use, flush the entire system with clean water, inspect and clean filters and strainers, circulate an approved cleaning solution throughout the equipment, and rinse the system thoroughly before the next application.

Nozzles and screens should also be removed and cleaned separately.

Maintaining detailed cleanout records, wearing the required personal protective equipment, and disposing of rinse water according to regulations are additional best practices that help ensure safe, effective pesticide applications while protecting crops and the environment.

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