Reducing Spray Drift During Applications

July 10, 2015

Drift occurs when liquid droplets from a sprayer application fall off-target from their intended location. Avoiding pesticide drift is a familiar battle to people in our industry. We all want to avoid waste and get the most out of our applications. Let’s explore the types, effects and ways to reduce drift to make it better for your business and our environment.

Types of Pesticide Drift:

  • Spray Drift: Also referred to as droplet or particle drift, spray drift is the unintentional dispersal of off-target chemical spray particles during application caused by air movement.
  • Vapor Drift: This type of drift is less known. Also known as volatilization, vapor drift happens when settled spray becomes vapor and rises from the plants or soil before drifting. This can occur days after application.

Effects of Drift: Pesticide drift is an unwelcome part of any sprayer’s job. The severity of the drift’s effects will vary depending on the setting. Not only is spray drift costly to your wallet, but also your surroundings. Spray drift can be:

  • Harmful to Plant Life: A more realistic concern for any residential sprayer is the effects drift can have on surrounding plant life. Pesticide drift can damage and even kill plant species they weren’t intended to target. You want to avoid a situation where spray drift that’s intended to kill lawn weeds ends up harming nearby trees or shrubs.
  • Harmful to Water Sources: Typically more of a concern in rural areas with major pesticide applications, drift of pesticides into water sources can cause contamination issues. Pesticide contamination can harm and even kill wildlife in the polluted bodies of water.
  • Harmful to Humans: Like water contamination, the threat of pesticide drift to humans is more relevant in farm settings with broad-range applications, but it can cause acute and chronic health issues including skin and respiratory issues.

Reducing Drift: Seeking to reduce spray drift will require increased understanding of weather conditions and equipment parts. Addressing both factors can greatly reduce spray waste and its undesired consequences.

  • Environmental Considerations
    • Wind: Ideal spraying conditions are when winds are between 3-10 mph.  Typically, wind speeds are lowest in the early morning and evening.
    • Temperature: Avoid spraying in extremely high temperatures whenever possible. Hot, dry weather results in smaller droplets (due to shrinkage from evaporation) which have greater drift potential.
  • Equipment Considerations
    • Lower Pressure: Both your nozzle and sprayer pressure affect droplet size. Reducing your spray pressure will allow for larger droplets that won’t drift as much.
    • Nozzle Selection: Using a nozzle that produces larger droplets, while also replacing worn nozzles, can go a long way towards minimizing drift.
    • Drift Retardants: Additives are available that help increase the viscosity of your spray, which in turn, decreases drift. Be sure to check the compatibility of any additive with the chemical you’re spraying.

Be sure to get the most out of your sprayer by following these suggested measures in an effort to reduce drift. In the process you can save money and reduce unintended harmful effects on the environment.