It could happen anytime. As drone fever sweeps across Western Canada, a farmer is eventually going to ask an agrologist or crop advisor to teach them how to spray pesticides with drones.
What do you do? Igor de Albuquerque advises extreme caution.
“If the product in question does not include drone usage on its label, promoting or advising on its use could result in regulatory violations, leading to penalties from the Pest Management Regulatory Agency (PMRA),” the forensic agrologist with the Saskatchewan Ministry of Agriculture wrote in an email.
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Producers have been using drones, otherwise known as unmanned aerial vehicles (UAVs) or remotely piloted aircraft (RPA), for scouting, mapping and managing cattle on pasture. With the advent of drones capable of spraying crop protection products, some growers have tried it regardless of legality.
Only four products have so far received agency approval for application using drones and none are directly related to agriculture. Garlon XRT herbicide controls vegetation in non-crop scenarios and the others are larvicides for mosquito control.
This effectively makes it illegal to spray any ag pesticide by drone and there are fines up to $10,000 from the PMRA for those who do so.
Liability is another risk, said de Albuquerque.
“Agronomists could face liability issues depending on their contract or agreement with the grower, especially if they work for a retailer, which might be viewed as advertising a product in violation of regulations.
“Such situations should be addressed by the appropriate licensing body, such as the Saskatchewan Institute of Agrologists.”
However, this may be a moot point. Unless an agrologist has the necessary training, the easiest thing to tell inquiring producers is that they’re not qualified. Transport Canada sets the requirements for instruction on spraying with drones and among them is years-long experience.
Specific penalties for agrologists who show farmers the ropes of drone application are hard to pin down, even for those as close to the subject as Ross Breckels, a senior scientific evaluator with the PMRA who chairs the department’s internal RPA working group.
“If an agronomist or a non-applicator advises an applicator to spray a pesticide when drones aren’t on the label, I guess it would be hard to penalize them, but maybe they would get their wrist slapped and have the talking to. But I don’t think there’ll be a monetary penalty involved.”
Markus Weber is a central Alberta professional agrologist and drone salesperson. He holds drone spraying clinics to help students get a feel for these aircraft: how to use them, calibrate them and measure the results of application. Students get into the field for spraying instruction, he said, but not with pesticides.
“We actually have them using the tool to create missions, to accurately hit targets, to calibrate, but it’s all with water in the tank. We don’t teach them how to use the pesticides. We teach them how to use the drone spraying tool or drone spreading tool for granular products.”
Weber teaches his students how to physically operate a drone and about the risks and regulations from the PMRA and Transport Canada, which oversees the aircraft-based regulations.
“We have an hour, hour and a half, on all the regulatory aspects of doing this and that includes aviation regulations as much as it includes pesticide regulations,” he said.
“When I teach people how to use a drone for spraying, I teach them how to use it generally for spraying and if they are going to use it for spraying pesticides off-label, they know that what they’re doing is off-label and what the legal status of that is.”
RPA have their share of advocates and skeptics. In an interview earlier this year, Tom Wolf, owner of Agrimetrix Research and Training and a go-to sprayer guru, outlined some of the risks.
Because drones have smaller tanks and lower water volumes than other aircraft, spray droplets tend to be very fine and run the risk of going off-target, creating potential for spray drift, he said.
“The drones, by necessity, will be spraying low water volumes. A ground sprayer will be spraying five to 10 U.S. gallons for herbicides. The drones will likely be spraying two (gallons).
“These drones are somewhat limited in what droplet size you can produce. You will have to produce a smaller droplet in order to get adequate coverage with lower water volumes.
“I don’t see a way around that. You don’t have that coarse or very coarse or even extremely coarse spray categories available to you for low water volume drone spraying.”
Weber does not agree. Even if he did, leading RPA manufacturers such as DJI, XAG and Hylio are already manufacturing droplet-adjusting drones that create less drift-susceptible droplets.
“Historically, most spraying has been done with a flat fan nozzle. And the basic principle is you have high-pressure water going through a small hole and that hole atomizes, it meters, and it creates some kind of a shape: a flat fan, typically.”
Modern spray drones feature three components that enable application: the atomizer; pumps that do the metering; and propellers that create the “fan” or deposition size using downward pressure. Droplet sizes can be adjusted.
“A drone operator is able to change droplet size from as low as 50 or 100 microns — extremely drift-prone droplets but in some cases necessary, say, for an orchard where you’re trying to penetrate a canopy for insect control. In those cases, some really fine droplets are called for,” said Weber.
“And then in situations where you have higher winds and you need to control drift in more of a typical Western Canada field scenario, then the larger droplet size makes sense, and that one tool lets you do all of that.”
Weber said more research is needed on how propellers distribute droplets to create less drift. However, he argues that drift from drones is no worse than what’s created by manned aircraft, which some producers legally hire for spray operations.
“The biggest benefit of drones is that they have downdraft,” he said. “Those propellers are largely pushing air down, but they’re also pushing those droplets down towards the ground and that reduces their dwell time in the air, improves coverage on the plant, improves canopy penetration. So that propeller is actually a big part of why these drones will have such great benefit.”
Four categories must be satisfied before the PMRA makes an on-label decision for a pesticide and its method of application: drift, efficacy, maximum residue limits and operator and bystander exposure.
The PMRA itself doesn’t collect this data, instead counting on chemical companies to submit pesticides for on-label drone use based on their research. Some, including Breckels, have in the past suggested there isn’t a lot of activity on that aspect.
However, Breckels is more optimistic today, thanks to research conducted around the world. Probably the biggest example is the work of the Unmanned Aerial Pesticide Application System Task Force.
It is a consortium of eight ag chemical companies that formed in 2021 to generate drone-spraying data on off-site movement, operator/handler exposure and human dietary exposure for regulatory authorities around the world.
The eight companies include BASF, Bayer CropScience, Corteva AgriScience, FMC, Gowan, NuFarm, Syngenta and Valent.
The results could bring good news for farmers who want to use drones for pesticide application, said Breckels.
“They have been conducting worldwide drift trials in 2023 and some are still ongoing in 2024. They are going to submit their data to the PMRA sometime this fall as well. So we should have some data coming in, which hopefully is useful and will help in getting more drones on the labels once the applications come in.”
Breckels also noted a presentation at the American Chemical Society conference in August that hinted at “encouraging” preliminary results from residue trials.
“They’re hopefully going to provide the PMRA with the data from those results in the coming months.”
The task force has an annual budget of about $4 million per year.
“It’s not an insignificant amount of money that they’re putting into this, so obviously there is a lot of interest from chemical registrants.”
The popularity of spray drones, once common ag pesticides are registered, is another matter, said Breckels. They won’t likely replace ground sprayers or manned aircraft as application methods.
“They’ll work in conjunction with them, so the pesticide companies would still get their revenue from field sprayers and air applicators.”
Weber says the first ag products approved for drones will likely be fungicides and chemicals for various niche uses.
“That’s been proven true with Garlon XRT,” he said.
