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Posted 15 February 2010. PMN Crop News.

New Drift Risk Advisor Unveiled for Spray Applicators

Source: Oklahoma State University Press Release.

Stillwater, Oklahoma (February 8, 2010)--A new tool to help applicators determine potential spray times using weather forecasts is being offered through Oklahoma’s Mesonet agriculture weather team.


“The Drift Risk Advisor was introduced this January, in time for this year’s spraying season,” said Al Sutherland, Oklahoma State University Mesonet agriculture coordinator. “The advisor is for anyone who applies chemical sprays, farmers, custom applicators, lawn care professionals and home owners.”

In terms of Oklahoma’s multi-billion dollar agricultural industry, farmers and professional applicators spray crops in hopes of eliminating unwanted pests. If weather conditions are not ideal, there is a risk of pesticides or herbicides drifting to neighboring cropland.

“Drift is a major concern in Oklahoma,” said Randy Taylor, OSU Cooperative Extension agricultural engineer. “Spray or vapor from an application moving off target can potentially damage sensitive crops in the area. Damage can range from minor and having little or no effect on yield to having a devastating effect and possibly even destroying the crop entirely.”

Prior to the development of the Drift Risk Advisor, producers and applicators could access National Weather Service forecast graphs and tables, and then sort through the charts and numbers.

For nearly two years, OSU Cooperative Extension and Mesonet faculty have discussed and developed the new Drift Risk Advisor. It was tested and evaluated by farmers and professional applicators during development.

Sutherland said the new tool is easy to use and straightforward in the information provided.

After a few inputs, the applicator has an 84-hour forecast table that shows when weather variables fall within or outside of desired values. The tool is based on a forecast, so the user must specify the conditions that are acceptable for spraying.

“Changing these conditions could change the results,” Taylor said. “Also, the forecast can potentially change. It’s important for the user to be aware of the actual conditions when they are applying pesticides or herbicides.”

Taylor and Sutherland caution that, while extremely useful, the Drift Risk Advisor does not replace good judgment on the part of the applicator or applicator responsibility to follow label restrictions based on actual field conditions.

In addition to using the new Drift Risk Advisor, the following steps should be taken to help prevent drift:

•Select a nozzle type that provides a coarse droplet;

•Reduce spraying pressure;

•Move the boom to the correct distance from the target;

•Understand the effect of nozzle size on spray effect;

•Spray when winds are blowing less than 10 miles per hour;

•Know wind direction;

•Avoid temperature inversions; and

•Consider drift additives.

More information on the Drift Risk Advisor is available at on the Internet.

The Oklahoma Mesonet program is a joint effort between OSU and the University of Oklahoma, consisting of more than 110 automated weather monitoring stations across the state. There is at least one Mesonet station in each of Oklahoma's 77 counties.

Donald Stotts