Lynn Sosnoskie: ‘Weed-It valuable for future weed control in perennial crops’

Sosnoskie, Assistant Professor of Weed Ecology and Management in Specialty Crops at Cornell AgriTech in Geneva, New York and her team have conducted multiple trials with a Weed-It Quadro system.

The researchers needed some time to properly get the first trial with the Weed-It technology going. “It’s not plug-and-play”, Sosnoskie emphasises. “You can’t just turn it on, and you’re off and driving. It took us time to learn calibration, and what is going to trigger an error. It’s new technology, and there is a certain level of complication. I wouldn’t say it’s simple, but it’s also not overly complicated.”

There was good support from the company that delivered the sprayer, Sosnoskie says. “They came out and custom-built it for us. They worked with us to get the unit set up. There is a learning curve, but it is not insurmountable. And optimisation means a lot to growers. It’s worth the effort.”

In May 2022, Sosnoskie and her team compared two application strategies in a targeted sucker control trial at the U.S. Cornell Lake Erie Research Extension Laboratory in Portland: a vision-guided Weed-It Quadro and a backpack sprayer.

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Level of control

The treatment plots had whole rows of 24 to 29 Concord vines spaced 9 feet apart, with individual vines spread 8 feet apart within the row. The mean sucker size was 6 to 8 inches. The researchers applied three spray treatments, Aim (carfentrazone-ethyl, FMC), Rely (glufosinate-ammonium, BASF), and tiafenacil (Gamma, Helm).

The ATV-mounted Weed-It Quadro (TG-3 nozzles, 20 gallons per acre, 5 mph riding speed) and backpack sprayer (11002 nozzles, 20 GPA, 2.5 mph walking speed) both achieved 80% to 90% control at seven days after treatment.

The spot spraying technology could detect weeds and treat the weeds

“My hope was that I would see the same level of control”, Sosnoskie says. “That was my working assumption. We saw it two years earlier with weed control in grapes. We knew that the spot spraying technology could detect weeds and treat the weeds. So, they should be able to see and spray the suckers as well. My hypothesis proved to be accurate.”

The Weed-It Quadro used 40% less herbicide, but that figure could have been much higher, up to 80% or more. “Because we had a cover crop planted between our rows, the inside sensor was detecting the edge of this cover crop. So, it kept on turning on the nozzle to spray the edge of the cover crop. We would have used a lot less herbicide for just controlling the suckers.” In new trials of the team, starting soon, cover crops will be mowed.

A good baseline weed control

The 2022 trial resumed in 2023, but was moved – without Rely – to a nearby USDA breeding block with M7 apple rootstock. “It was a two-pronged trial”, Sosnoskie explains. “We wanted to know if tiafenacil was as effective as carfentrazone for controlling suckers. And they performed equally well. We also compared the WEED-IT and the backpack sprayer again, and we got the same level of control.”

Sosnoskie and her team also compared the Weed-It and backpack sprayer in a practice trial involving Rely and hundreds of horseweed plants. This was when the team first used the Weed-It sprayer, and needed some time to get the Weed-It Quadro system going.

“There is a learning curve associated with the use of the technology. When we got the Weed-It, and were able to install it and use it, the weeds were already a bit denser. We did get good weed control. We reduced the cover of the weeds. We didn’t do as well as a banded application under the vines, because the weed density was just a lot higher.”

According to Sosnoskie, the value of the spot spray technology really shines where there is a good baseline weed control to start off with. “We did not actually trial when the efficacy and value of vision spray systems are probably going to start going down. That is something we have been talking about doing. I’m hoping that we can start answering these questions in the next couple of years.”

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Just getting started

“We can set up different weed densities and evaluate that. We would go in and change the weed cover and the weed sizes under the vine, and would be doing comparisons of performance. We did see that, starting with a weed coverage of 50% in 2021, the Weed-It sprayer wasn’t working as good as a banded application. But in 2022, with a 5% weed coverage, we had a much better success rate.”

After several trials with the Weed-It system, Sosnoskie says she is optimistic. “There is a lot of work being done, using vision-guided weed control in annual cropping systems. And there is the work that John Deere and Blue River are doing, looking at our large acreage agronomic crops. There are laser weeding systems and targeted herbicide spray systems in vegetable crops.”

We are on the cusp of something really promising

“But there has been less effort put into the weed control in perennial systems. But I’m optimistic that these already commercially available technologies can be adapted to our under canopy weed control systems. Even though we have been working with it for only a few years, and we are only just getting started.”

The Weed-It Quadro also performed well at weed control in a blueberry trial conducted by Dr Thierry Besancon, an Associate Extension Specialist in Weed Science at Rutgers University. Across all herbicides, there was no difference between the Weed-It sprayer and backpack sprayer. “I’ll be doing more work with sucker control this year, and I’m hoping that my colleague Thierry Besancon will do the same in blueberries, and we’ll have some good – much more solidified – data”, Sosnoskie says.

A lot of value

“We are on the cusp of something really promising. I see it having a lot of value going forward. With our targeted spray systems, we have the opportunity to put out less product. That means a lot from a crop safety standpoint. Enhanced crop safety may allow research evaluating new herbicides that could control herbicide-resistant and perennial weeds. These new systems can prevent non-target movement and harm to non-target species. It could have implications for greater safety for farm workers. And there is a potential for ultimate cost saving.”

“We are really focused on new technology, and would like to work with growers to ask them what technology they are interested in. And then build some kind of innovation farm. If we can get full funding for our Specialty Crop Research Initiative in the next three years, we can start looking in real detail at vision guided spray technology, electrical weeding, GPS guided autonomous robotic systems, all that new technology in our perennial crops.”

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