Pesticide spray drift can cause farmers all sorts of trouble, including angry neighbors who lose crops, heat from government agencies, wasted money and poor control of target pests.
“Controlling spray drift is one way farmers can begin to reduce the negative image many of the non-farming public have of chemical pest control,” says Les Slunecka, with Spraying Systems Company, which serves Texas, Oklahoma and Arkansas.
Slunecka, addressing the Ag Technology Conference recently on the Texas A&M-Commerce campus, said spray drift is “the nature of the business in the Southwest. The wind seems to be blowing all the time.”
Drift presents a challenge, Slunecka said, but not an insurmountable one.
“A number of factors affect drift,” he said. “Wind, heat, droplet size, spray pressure, boom height and speed of the applicator vehicle all play important roles.”
The key, he said, is for applicators to manage the factors they can and work around those they can't.
“We can do nothing about temperature and humidity,” he said. “We can't control air movement, either direction or velocity. And we know that high wind speeds and low humidity increase drift potential. We can't change air stability patterns, inversions, and we can do nothing about topography.”
So concentrate on manageable factors, he recommended. He outlined 10 steps farmers can take to reduce drift.
- Spray higher volumes.
- Select a nozzle with a larger spray particle.
- Lower the sprayer boom height.
- Spray when wind speeds are lower.
- Reduce spray pressure.
- Reduce vehicle speeds.
- Avoid spraying in adverse weather conditions.
- Consider using buffer zones around fields.
- Replace worn nozzles.
- Use emerging technology.
New technology, he said, includes shields, air-assist sprayers and global positioning systems. “GPS offers us a tool to manage specific fields,” he said. “It's a good way to situate buffer zones and to record spray application data for records.”
He said the most important element in preventing spray drift drives the spray rig or flies the plane over the fields. “The applicator is the key,” he said. “It's imperative that every pesticide applicator read and follow labels, check environmental conditions, select the right nozzles and adjust to changing weather conditions.”
They also must check spray nozzles tips regularly. Excessive wear, Slunecka says, increases potential for drift. Some tips, depending on material, wear longer than others.
“Base replacement decisions on catch tests,” he said. “But some general guidelines suggest replacement after 1,000 to 5,000 acres. Poly tips may go after 1,000 acres, brass after 5,000, stainless steel after 2,000 and ceramics after 4,000 acres.
“It only takes a minute to check nozzle tips and compare them to a simple chart,” Slunecka said.
He said the type of chemicals applied and cleaning method also affect nozzle wear.