Managing herbicide drift is the law

From Southeast Farm Press

Keeping herbicides from drifting off target is the law and “it’s the neighborly thing to do,” says a University of Georgia weed specialist.

“If you look at our agriculture community, it’s family living next to family. If herbicide drifts onto another grower’s field, the impact from that drift could be significant. It could reduce the bottom line, damage the crop,” said UGA Extension weed agronomist Stanley Culpepper. “We need to manage drift, obviously, to be good neighbors, but essentially it’s the law.”

Culpepper implores farmers and pesticide applicators to exercise ‘common sense,’ when applying their chemical treatments. This task involves managing a lot of factors.

“Wind speed, spray pressure, sprayer speed, height of the boom above the target, herbicide product and formulation, and adjuvants must all be considered when developing a plan to avoid off-target herbicide movement,” Culpepper said.

Off-target movement comes from spray droplet drift or vapor drift. Droplet drift is a result of spray emerging from a spray nozzle and breaking into droplets of varying sizes; large droplets fall more quickly to the ground while smaller droplets remain in the air for a longer period of time and are more likely to move off-site.

Culpepper says growers have numerous options to help reduce spray droplet drift.

Using nozzles and spray pressures that produce the maximum size spray droplets for the selected herbicide is one part of the drift control program. But Culpepper stresses farmers should do their homework as some herbicides are not effective when spray droplets become too large.

Vapor drift usually occurs with high volatile compounds when the herbicide contacts the target (plant/soil) as planned, but later lifts back into the air as a result of very specific environmental conditions.

Growers can limit drift by reducing the boom height to the lowest point that allows adequate spray coverage without boom destruction. Two-foot above the weedy target would be ideal when feasible, Culpepper said. Drift control agents, following herbicide label recommendations, can also be an effective part of a drift control plan.

The greatest method to reduce drift is common sense. Do not apply a product in winds that move the herbicide from the target area, he said. Most herbicides should be applied when wind speeds are between 3 and 10 mph, but even at these speeds care must be taken to avoid spray movement into sensitive areas.

Growers can also reduce the potential for herbicide volatility by avoiding product formulations that are highly volatility. For example, 2,4-D esters are much more likely to produce damaging vapors compared to 2,4-D amines, Culpepper said.

As farmers adopt new technologies, off-target movement should be rapidly reduced, he said. “As these tools and methods become available, grower adoption will occur as managing off-target movement is critical for our agricultural communities as farmers strive to be good neighbors and true environmentalists,” Culpepper said.

Real time wind speed data is available through UGA’s Georgia Automated Environmental Monitoring Network.

Webinar: Pesticides in Foods: Residues, Regulations, Risks and Realities

March 6, 2 PM


Pesticides are frequently detected in many foods and their presence in food represents an area of great concern among many consumers and agricultural decision makers.  Pesticide residue regulations, both in the U.S. and internationally, are complicated and often counterintuitive and frequently lead to scientifically inappropriate conclusions concerning levels of risk posed by pesticide residues.  This session is designed to clearly discuss the process by which pesticide residues are regulated and the risks posed by residues in foods.  Specific attention will be given to pesticide residues in imported foods, organic foods, and fruits and vegetables alleged to contain the greatest levels of contamination (aka “Dirty Dozen”).  The goal of the session is to allow participants in all aspects of the agricultural/food sector (conventional and organic producers, processors, distributors, regulators, legislators, marketers, and consumers) to gain a better understanding of this complicated topic and to develop strategies to allow them to appropriately address this topic with their clientele.

What you will learn:

  • Consumer concerns regarding pesticides
  • Pesticide residue regulation – U.S.
  • Pesticide residue regulation – international
  • Residue monitoring – what does it show? What does it mean?
  • Differentiation between violative and “unsafe” residues
  • Assessing risks from pesticide residues in foods
  • Pesticides in imported foods
  • Pesticides in organic foods
  • The “Dirty Dozen” list of fruits and vegetables allegedly containing the highest pesticide residue loads
  • Food safety in perspective

Who Should Attend:

  • Conventional food producers
  • Organic food producers
  • Food processors
  • Food retailers
  • Food distributors
  • Government regulators and inspection personnel
  • Legislative staff involved with pesticide issues
  • Media representatives

Presenter–Dr. Carl Winter:

Dr. Carl Winter is the Director of the FoodSafe Program and an Extension Food Toxicologist in the Department of Food Science and Technology at the University of California at Davis.  Prior to coming to Davis in 1991, he was an Extension Toxicologist at the University of California at Riverside from 1987-91, a science writer for the Richmond-Times Dispatch newspaper in 1985, and an Environmental Hazards Specialist with the California Department of Food and Agriculture from 1980-83.  He holds a Ph.D. in Agricultural and Environmental Chemistry and a B.S. in Environmental Toxicology, both from the University of California at Davis.  His research and outreach work focus upon pesticide residues and naturally-occurring toxins in foods.  He has frequently been invited to testify before the U.S. Congress on pesticide/food safety issues.  He was a member of the United Nations/World Health Organization’s Joint Expert Committee on Food Additives and the U.S. Food and Drug Administration’s Food Advisory Committee. He was recently announced as the 2012 recipient of the prestigious Borlaug Council of Agricultural Science and Technology Communication Award.

Purchase Options:

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For more information please contact us at  Customer Service or call us at 215-465-7233.

Once you register for the webinar and/or recording, you will receive an email confirmation of the registration and information you will need to join the online event.

Aaron Brown

Food Seminars International