Launcher shoots dispensers into tree tops.
Brett Bunker shows off the launcher he uses to dispense pheromone-containing capsules in apple trees. The clip in the magazine holds 25 capsules. Left: When the Tangler is launched, the capsule splits and the string wraps, bolo-like, when it strikes a tree branch. Early in the season, there is no foliage, so the Tangler wraps without interference.
There is some disagreement about how long it takes to put 200 to 400 twist-tie pheromone dispensers in an acre of apple orchard to provide mating disruption of codling moth, but it’s a while—especially if the trees are tall and it takes ladders to reach the best placement sites in the upper third of the canopy.
But Brett Bunker can put in 400 pheromone dispensers in about 18 minutes; it takes longer if the launcher jams.
Brett Bunker and his wife Chandra are in the final stages of perfecting the Tangler.
Instead of a twist tie, two small cups containing pheromone and connected with an 18-inch-long piece of cotton string are shot into the tree canopy with a modified paint-ball gun. When the string contacts a branch, it tangles in place, bolo style.
The bolo rarely misses a target and tangles so thoroughly it can be removed only with extreme patience or by cutting, Chandra says.
Brett Bunker provided a demonstration during a September field day attended by about 40 chemical company representatives at the Trevor Nichols Research Center near Fennville, Michigan. His demo elicited the predictable response:
Why didn’t I think of that?
Actually, that’s how it started.
Chandra Bunker has a master’s degree in entomology from Michigan State University. She used her knowledge to start a consulting business called Ridge Quest in 2001. It’s located near Sparta, Michigan. Now Chandra, with her husband of 14 years and three young children, are launching a new venture. Brett, who is vice president, works with his wife, the president, after he left the commercial construction business four years ago. There are no other employees.
“I can do that”
As they tell it, it started four years ago. Chandra’s consulting business was doing so well she needed to hire someone to help, and she hired Brett. Chandra was telling her husband how mating disruption works and said growers would use it more if placing the pheromone dispensers was not so labor-intensive. Just like that, he said, “I can do that.” The bolo idea and the paint-ball gun jumped into his head immediately. “I saw it right away,” he said.
Brett left commercial construction just about six months before the industry collapsed—a lucky move, it turned out—and brought with him some useful skills. He built the launcher and magazine in his garage, using a computer-aided design (CAD) program. He bought a small computer numerical control (CNC) device to drive the computer-aided manufacturing (CAM) to build the barrel and the magazine that holds a clip of 25 “cap and cup” pheromone dispensers that they call modules.
“I just milled it out in my garage,” he said. “It would have cost me $55 an hour to hire someone else to do it.” He took his original idea to a prototyping company, but learned it would have cost $11 each to make the modules.
Instead, he hired a local company, Paramount Tool and Die, to make a mold and now uses a plastic injection machine to make the plastic capsules. “This is a step up from the turkey fryer I first used to melt the resin,” he said.
While Brett was perfecting the launcher, the magazine, and the modules, the two were also working to perfect the actual pheromone release process. Pheromones are expensive to buy, Chandra said, but they are commercially available for several insects. For now, they are focused on codling moth. The hard part is getting timed release.
Working with Dr. Larry Gut and other entomologists at Michigan State University, they developed a release device placed inside the two cups at the ends of the strings. It releases pheromone evenly over 150 days.
That is longer than needed for codling moth disruption, but it will allow growers to apply the dispensers as much as two months before bloom, after the trees are pruned but before there is any foliage. Foliage interferes with the Tangler’s tangling action. “You have until petal fall in Red Delicious to get them applied,” Chandra said.
Gut and Dr. Jay Brunner at Washington State University have both tested the Tangler, mostly to determine that it does effectively release the pheromone and work at least equivalently to other dispensers, like the twist ties.
Plastic used to make the modules will be biodegradable, as is the string, but each unit will probably persist more than one season. The Bunkers plan to produce them in several colors, so growers can easily see what they applied in the current season.
Walk or ride
In his demonstration, Brett carried the aluminum metal launcher holding the clip and powered by commercially available compressed air canisters like those used in paint ball guns. He walked briskly, shooting left and right into the tree tops. The launcher is pump action, not automatic.
“Walking on the rough ground is hard work,” Brett said. “I think growers will find better ways. They will probably use vehicles.”
Carrying extra clips is important, since each holds 25 rounds. He’s packaging them in pouches that hold 16 refillable clips.
The design of the individual bullets, or modules, is complicated. The 1/2-inch by 3/4-inch rectangular box is made of two parts and contains the pheromone and the string. When the module is shot from the launcher, it opens and flies until the string contacts a branch, where it rapidly wraps.
How far it flies is governed by the air pressure in the launcher (it’s adjustable) and the aerodynamics of the bullet, and also by the diameter of a hole in the bottom of each capsule. That air pressure is what causes it to split open as it flies. Different weights of the capsule and different amounts of air pressure determine how far it will fly.
Other insects next
The Bunkers say they would like to expand into mating disruption of other insects, like oriental fruit moth and obliquebanded leafroller, and perhaps into applying attractants and repellents. Capsules could be differently shaped or contain additional compartments for application of several pheromones in one dispenser, each kept separate.
They hope to have a product available for use in orchards by the spring of 2013. Meanwhile, they need to get a business plan in order, get loans, and perhaps investors, and put together a plan to manufacture and distribute.
“So far, we’ve done everything out of our own pockets,” Brett said.
The Bunkers said they might decide to offer a service of applying the pheromone dispensers. They will be working with engineers this year to develop an automated assembly process for making the Tangler.
Brett thinks sales will be no problem. Growers keep asking him when he’ll have a product ready to go. So far, the Bunkers have been sticking to a discipline—perfecting the product, getting it tested, and getting everything properly protected by patents. “You don’t get a second chance to make a first impression,” Chandra said. “In another year, we should have a decent product at a decent price.”
"We're just about there," Brett said.