Reduce Pesticide Drift And Impact to Sensitive Areas

Posted: May 9, 2014

The wind has been beneficial this spring to help dry the soil to allow field work but too much wind when you want to spray can be detrimental. Penn State Extension Weed Science Specialist Dwight Lingenfelter has some tips to reduce herbicide drift and keep your herbicides on target.

Keep in mind the objectives of any spray application are to balance productivity, efficacy, and prevent off-site movement of pesticides. In some situations, this can be easier said than done. Below are several things to consider to help reduce particle (not necessarily, vapor) spray drift.

Spray at low wind velocities (<10 mph); in general, winds are less early in the morning or late in the evening. Reduce spraying pressures; lower pressures allow for larger droplet sizes. Additionally one can increase carrier volumes/application rates; if possible use 20 gallons or more/acre instead of 10 gallons or less/acre. Another step is to choose the proper nozzles with coarse spray droplets; there are several companies that manufacture nozzles that are designed to reduce drift; some examples include: TeeJet AI, AIXR, and TTI; Greenleaf TurboDrop XL; Hypro Ultra Low Drift, among others. Also we can use lower spray boom heights. Always make sure to use nozzles that have 110° or more spray angle which allows the boom to be lowered more than nozzles with lesser angles, but ensure spray pattern and proper overlap is maintained.

One can reduce sprayer ground speed (<10 mph); faster speeds cause more boom bounce and a spray vortex to occur sending spray droplets higher in the air. Using drift retardants is another option. There are many good products on the market for this purpose. One should spray when wind direction is away from sensitive crops, homes, etc. A big step would be to invest in “high-tech” sprayers (e.g., pulse modulation); some of the new sprayers use a pulsing system to assist in better application and drift reduction

Only if absolutely necessary, avoid certain systemic herbicides (2,4-D, dicamba, glyphosate, etc.) when spraying near very sensitive crops (e.g., grapes, fruit trees at “bud break”).  Selection of other products may be prudent to reduce the concern of serious injury potential. Consider burndown herbicides such as Gramoxone, Liberty, Sharpen, metribuzin, or others.


(Contributed by Leon J. Ressler, District 17 Director as part of his Now Is The Time Column for May 10, 2014)