Aerial Applicators Can Join Resistance Fight
Aerial application, when used in a systematic approach to crop protection, can deliver prompt, accurate and efficient control of pests and resistant weed species.
Part of a Special Report sponsored by Air Tractor
September 6, 2012
As resistance to valuable crop protection tools continues to emerge, industry stakeholders are rallying to find ways to combat the problem. Aerial applicators can indeed lend a hand.
Our crop protection company and extension contacts said growers should start with a systems approach that includes crop rotation, tillage, variety choice, varied modes of action, local risk evaluation and the like – then understand what aerial can bring to the table. What it can deliver primarily, they say, is prompt, accurate, and efficient control of pests that greatly reduces the development of resistance. If you kill the pest, it can’t become resistant.
Just the physics of aerial application favor a complete kill because products very effectively reach intended targets, says Dr. Gary Fellows, tech service, fungicide, and seed treatment manager with BASF Corp. He explains that aerial applicators get a very good mixing of spray within the canopy because of the air buffer created under the wing. Turbulence there forces spray downward. In fact, Fellows says BASF has done coverage trials that show “very, very good coverage down deep” even into a tight canopy such as in narrow row soybeans.
Timeliness of application is another benefit aerial brings. Growers want to hit pests at the right development stage, for instance, when weeds are short and easier to control instead of when they’re large. With planes, applicators can go in fields any time, especially when pests are vulnerable, says Dr. Scott Bretthauer, pesticide safety extension specialist with the University of Illinois. They don’t have to wait for soil to dry, as in cases where wet conditions may prohibit a ground rig.
“And in cases where Mother Nature will not submit to ground application, aerial provides a mechanism to use the proper tools to combat already resistant insects and weeds,” notes Jim Loar, senior vice president of sales and marketing at Wilbur-Ellis Co.
Like ground operators, aerial applicators are now tuned in to precision ag techniques to enhance pest control, says Andrew Moore, executive director of the National Agricultural Aviation Association. He notes that grower data (soil testing, crop scouting, and yield monitoring) is combined with GPS, satellite and aerial imagery, and variable rate technology to achieve effective pesticide applications. In fact, according to NAAA’s survey, 21% of its members are using VRT.
Simple wise stewardship of products is vital. Mike Carrell, branch manager at Ceres LLP, Wingate, IN, says his company makes it a policy not “to just blanket apply” corn fungicides on every acre. His aerial contractors treat fields that have the potential or already have the fungus present – those planted to corn after corn or that have a history of disease in the past.
Resistance And Drift
Bretthauer has found that some in the agricultural community “have a deathly fear” of aerial application due to a great concern about increased drift risk. Part of the issue here is that drift can cause unintended lower rates of product that won’t completely kill pests, again, encouraging resistance.
“Reality is drift is primarily a function of droplet size, wind speed, and wind direction,” Bretthauer says. “We can set aircraft to have just as large of droplets as with a ground rig.” And he explains that in order to prevent drift, airplanes often don’t spray a whole field at once – they spray it in sections based on wind direction, returning at different times during the day to cover sites completely, traveling 150-160 mph. Ground rigs often don’t have the time to take this approach.
Then too, smokers are a tool unique to aerial to help gauge danger from drift. Paraffin wax is simply released onto the plane’s exhaust manifold and burns off to create white streams that clearly indicate wind direction, speed, and vertical mixing.
There is a tremendous need for the retailer/aerial applicator/agronomist to play a role as a trusted advisor to growers in resistance management, concludes Wilbur-Ellis’ Loar. Education and communication among the stakeholders will be essential.