Aug 4, 2016

Solid-set canopy delivery system on track

If a solid-set canopy delivery system proves to be an efficient way to apply chemicals and other crop control measures, researchers are confident tree fruit growers would benefit immensely through reduced application costs and significant safety advantages.

Matthew Grieshop, Michigan State University (MSU) professor of organic pest management, is one of the researchers on the multi- year project that includes development work through Cornell University and Washington State University. The project is currently seeking additional funding to proceed with further engineering and commercialization work.

“We’re really excited, and we’re really hoping we can get some (additional) funding to move this project into more of a production phase,” Grieshop told attendees at this summer’s open house and field day at MSU’s Clarksville Research Center. The system, which has evolved into a more portable approach, also could have broad application in other fruit crops, such as raspberries, blueberries and grapes.

The USDA-SCRI-funded Coordinated Ag Project began with a research and Extension team from Michigan, Washington and New York. Its goal is to develop and evaluate a solid-set canopy delivery (SSCDS) system for apples and cherries.

Developing and optimizing a resource-efficient SSCDS for multiple uses by tree fruit producers could help growers better manage chemical inputs, improve pest and crop management, and reduce labor and fuel costs, thereby enabling tree fruit producers to remain globally competitive and environmentally responsible, Grieshop said.

Researchers said the horticultural aspects of tree fruit production have undergone a revolution over the past four decades. Tree density has increased from 25 to as many as 2,500 trees per acre and tree stature and canopy volume have shrunk accordingly.

Foliar input technologies have not kept up with this change and growers still rely on tractor-driven airblast technologies designed to apply inputs to massive, spherical tree volumes although modern orchards present narrow linear canopies.

“The SSCD systems being developed by our team promise to revolutionize foliar input application,” researchers wrote in their Year 1 Summary Report in spring 2013. “Systems consisting of fixed microsprayers distributed throughout the orchard canopy have the potential to: increase spray coverage, reduce application time, reduce on-farm use of fossil fuels, and allow growers to make foliar applications when the orchard floor is impassable by tractors.”

The applications are fed by a pumping station that combines both a hydraulic and pneumatic delivery system.

“Our first proof of concept project was between 2012 and 2014,” Grieshop said at the Clarksville field day. “We got two good years of data out of that that showing we had equivalent pest management with this system in comparison with a traditional airblast sprayer. Last year, we did some retrofitting, in part thinking about the future of cherries, and the big change there.

“The first thing we did in the cherries was the emitters were just plugged directly into irrigation lines. In a cherry canopy this became very problematic because in cherries you have a large canopy that can block the emitters. To counteract that we moved to another system where we put our emitters on spaghetti tubing. So last year we refit our apples and repositioned our emitters on spaghetti tubing and they can be repositioned at will. So when you’re doing your training or pruning, if you notice that a main scaffold is blocking something, you can simply move it over so it’s not being blocked anymore. That’s our third concept.”

Grieshop said the original system fed and delivered chemical with water pumps enabling users to charge the lines. There are stop devices on the line that allowed a charge without the emitters coming on.

“You then raise the pressure above those check valves and you get an application. It takes somewhere between 12 and 15 seconds to put 100 gallons of spray volume on in a set, so it’s very rapid,” he said.

He said researchers have then used an air compressor with a low-pressure air front to return anything that is still left in the lines, back to a holding tank before increasing the air pressure once again to flush it all out and blow it clean.

“So it’s really a four-step process: charge the lines, apply your spray, clean the lines and then clear the lines. Our new concept turns it into a two-step operation. What it also does is to greatly reduce the amount of chemical needed to fill the lines.”

Grieshop described the biggest engineering challenges during the initial design: “You end up having to pump many hundreds of gallons of liquid into just your feeder lines to get the liquid to where it needs to be spraying. The new design does away with that, essentially.”

“The other exciting thing about where we’re headed is this new concept was born originally out of John Nye (of Trickl- Eez). He came up with the idea of having canister-fed systems, but we took it to the mechanical engineering department at MSU. A group of students came up with an entirely new process, which we’re putting into concept. The initial project was funded by the USDA-SCRI program, and we’re waiting to hear about funding for another round of this.

“If we are funded that project will focus largely on engineering,” Grieshop said. “I have a team of engineers and mechanical engineers who basically work on fuel- injection systems. They’re going to be helping us optimize nozzles. Right now, we’re using right off the shelf irrigation nozzles – well as the other operating components of the system.

“Another major objective will be to develop automated fault detection. What that would do is allow the applicator to say, ‘10 yards down, three rows in, I have a nozzle that’s either over-applying or under-applying,’ so they know there’s a maintenance issue that needs to be taken care of.”

Grieshop said the research includes significant spray coverage evaluation, including the use of water sensitive spray cards that display the spray pattern that’s received at the top and bottoms of leaves or fruit. They also use a tracer dye to determine the deposition.

“We can wash that tracer off the coated surfaces and know how many parts per million were distributed on a given leaf,” he said. “What we’re going to be doing this summer with this portable system is developing coverage data for a variety of other crops, so we are going to be working in raspberries, blueberries and grapes.

“In a full canopy we can start to get a feeling for what kind of coverage can we get with this approach in these canopies,” Grieshop said. “If we can show that we get on average about 30 percent coverage by surface area, we know that’s enough to give us good pest management on almost every system.

“It’s currently a demo system and a research tool,” Grieshop said of the latest concept displayed at Clarsksville featuring use of canisters to charge and manage the system. “Should we be funded; we will be retrofitting this system entirely with this type of design working with our engineer colleagues.

“This canister concept was originally designed by John Nye. Then our engineering partners came up with the idea of a seal. The real cool thing about this is that this becomes our fluid feed line – only fluid in this line – a lot of engineering. We can go with a very large line to get a very high volume of air without having to fill everything and have a lot of residual waste.

“Our team of entomologists and horticulturalists was fooling around for about three years and didn’t come up with a simple carburetor-type float mechanism. Should we be funded, we’re really excited. The automotive engineering group has a very nice instrumentation for measuring spray from nozzles so we can calculate droplet size, throw, weight, angle, sort of anything you could possibly imagine.”

A big attraction to the system is the time savings that takes place, he said.

“Its actual spray application is about 15 seconds per set, so if it takes 15 gallons to put on 100 gallons’ spray volume, conceptually what we envision is a block like this would have one or two manifolds on it. You could pull up in a cart, set up with a premixed tank – no different than you would have on an airblast sprayer – you’d have your worker jack into that tank and into the pump system. They’d flip a switch, charge it, that would probably take a minute or two. They’d flip another switch, the air compressor would come on, and be on for maybe 15 to 30 seconds to put the application on, 15 seconds to finish, and then they move on to the next manifold.

“The advantages to that are somewhat obvious, but for one thing, for early season scab control, if you are not on a really sandy, well-drained soil, if you’re on heavy clay soil, sometimes it’s really hard to get your sprayer through when you need to be getting primary scab control on. If you don’t need to take a tractor through the orchard, that ceases to be a problem.

“This is very quiet if you’re close to urban areas,” he said. “It’s not running an airblast sprayer in an orchard where that person who decided to build their $500,000 palace next to the farm country without thinking, ‘oh yeah, farmers spray,’ and then they get upset. They’re not going to notice because it’s very quiet, and you could do it in the middle of the night.”

Safety advantages could emerge from using the technology.

“From a skill perspective, we can get this mechanized to a point where the unskilled labor can do this very safely,” he said. “They don’t need to be out there where the Captan – or whatever else we’re applying – is being applied. They’re safely outside the orchard or perhaps in a cab tractor. So there’s a lot of speed advantages as well.

“And then of course from a labor saving standpoint, if we’re able to develop a system that can be commercialized that is simple to operate, you don’t have to worry about, is this person I’ve got driving the tractor how, are they going to handle the job?”

MSU graduate research assistant Paul Owen-Smith has started working on methods for changing the way spray volumes are applied.

“Should we be funded, we will continue to look at it as an idea of changing the way we apply volumes of pesticide,” Grieshop said. “Right now, think about the way we put on insecticides, if you’re putting on a cover spray for say, a plum curculio, early season. You’re putting on chemistries that you’re hoping you’re going to get at least seven to 10 days of activity out of. To achieve that, the tree is very rapidly growing at that point, so the rates you use reflect that. Essentially, it’s like painting a house with one coat of paint. You end up using a lot of paint and a lot of it doesn’t go where you want it to be. If we could perhaps put on a base coat at a higher rate, and then touch it up at shorter intervals, we might be able to use less volume of insecticide so there’s less active ingredient rate and manage our residues a little better.

“We’re moving forward where we’re seeing, certainly in international trade, residue limitations becoming a real issue,” Grieshop said. “That could become a real game changer. Also, it might allow us to move toward some softer biological-based pesticides. As an organic pest management person, that’s what’s driven me into this area. That said, I’m, not ever going to tell you guys what to spray. That’s not my job.

“So there is some hope that we could put pheromones out – much like we do with the aerosol emitters now – but in a much more distributing fashion. There’s just a lot of different possibilities.”

Delivering Solutions

The SSCDS project’s objectives include:

1) Develop, engineer and optimize SSCDS for orchard- scale use and materials delivery
2) Integrate and evaluate SSCDS with innovative apple and cherry pest management technologies
3) Integrate and evaluate SSCDS with innovative apple and cherry horticultural technologies
4) Determine the impact of SSCDS-based management practices on ecosystem services
5) Determine the economic impacts of optimized, integrated SSCDS on apple and cherry production system components and resultant ecosystem service values
6) Determine the sociological benefits of, and barriers to, grower adoption of optimized, integrated SSCDS into their production systems
7) Develop and deliver Extension and education activities and materials to increase producer knowledge and adoption of optimized, integrated SSCDS technologies.

— Gary Pullano, associate editor