Avoid pesticide contamination of water

Over the weekend, I walked around the neighborhood and everywhere I went people were spraying weeds with herbicides. Gardeners and landscapers use numerous pesticides at this time of year to keep a yard looking good. All these chemicals have the potential to contaminate surface and groundwater. I wanted to share some precautions that will help protect water quality.

Before applying a pesticide, evaluate the need, method and frequency of control. Rarely are pesticides necessary for plant health. Use pesticides only when nothing else will work and only in the minimum amount needed to control pests. Pesticides applied less frequently and in low concentrations are less likely to leach into groundwater. Choose the least toxic and least persistent chemical.

Gravelly or sandy soils that are low in organic matter have a high potential for groundwater contamination. If your soil is sandy, try to avoid pesticide use. Keep pesticides away from water sources or where they can run off into storm-water drains. These go directly to the river without treatment.

Always follow label directions carefully for the safety of people, animals, the environment and water quality. The label will tell you how to avoid groundwater contamination.

Buy and mix only the amount of pesticide actually needed. Measure the pesticide properly and carefully. More is not better! Avoid spills. Apply the pesticide at the appropriate time because efficacy is related to the stage of growth of the pest, whether an insect, a disease or a weed. Leave an untreated buffer zone around sensitive areas such as wells, groundwater recharge areas, springs, streams, wetlands, ponds, drainages or ditches.

Cleaning up and disposing pesticides properly is another important factor. Triple rinse pesticide containers and spray out the rinse water on a treated area. Never dispose of pesticides or pesticide containers near a water source. Store pesticides in their original container only, in a cool, well-ventilated and protected location away from pumps and water sources.

Pesticides frequently move with water downward through the soil, so delay irrigating for one or more days. Know if rain is forecast. However, some pesticides may need watering in to activate them, so read and follow the label.

Using pesticides in the home landscape should be a last resort. If you would like information on alternatives to using weed killers, insecticides, fungicides and other pesticides, please call me, 887-2252.

This information was adapted from A.C. Waldron, ohioline.osu.edu/

JoAnne Skelly is the Carson City/Storey County Extension educator for University of Nevada Cooperative Extension.