Pesticide drift from the site of application into non-target areas is a violation of state law governing legal application of pesticides; however, there is no state law that dictates restrictions when the wind is blowing at specific wind speeds.
Most pesticides used do not have specific wind speed restrictions. The few that do have restrictions range between 5-15 mph for application.
In urban areas, wind speed is often 10 mph or less than what it is at a weather reporting station because of trees, homes and buildings. Based on experience, the Minnesota Department of Agriculture (MDA) has found that complainants can have difficulty accurately judging problematic wind speeds and often overestimate the wind speed at the spray nozzle(s) height. The MDA uses its resources to determine if the application was made other than as specified by the manufacturer and/or whether it caused unreasonable adverse effects on the environment.
More questions about pesticide and fertilizer - health & safety: