UMD may have ultimate deer blocker
From hostas and yews to arborvitae and white pines, a growing deer population has been giving homeowners and gardeners along the North Shore fits in recent years.
The problem of hungry deer can be a headache for homeowners and an economic disaster for tree farmers, nurseries and foresters. And deer deterrents on the market until now tended to wash off in any rain.
But a Duluth scientist has developed a way for plants to absorb hot pepper concentrate into their roots and up into the leaves, rendering them too hot for deer to munch.
Tom Levar, a forestry and horticulture specialist for the University of Minnesota Duluth's Natural Resources Research Institute, developed the idea using a chemical first used to treat muscle soreness in racing horses and, later, human athletes. The benign chemical, called DMSO, absorbs quickly through animal and human skin and into the bloodstream.
Levar found out that it passes through plant "skin'' as well, and then combined DMSO with several bitter and otherwise unpleasant tasting chemicals. Pepper concentrate offered the best combination of being easy to use, natural and extremely effective.
"You can use it when the plant is first put in the ground or incorporate it into the soil with established plants,'' said Levar, adding that the plant will even emit a peppery smell. People "don't notice the smell as much, but the deer sure know what it is... It's not really clear which is the better deterrent, the smell or the hot taste. Usually it's one bite and they move on.''
The pepper concentrate, called capsicum, is natural and doesn't harm the plant.
The stuff also works great to keep dogs, cats, rabbits, mice, voles, moles and gophers from eating plants and young trees, Levar noted. In tests at an Alexandria tree farm that had suffered huge losses of young conifer trees to field mice, the repellent proved 100 percent effective.
Michigan-based Repellex, USA already has purchased the licensing rights from the university and has applied to the Environmental Protection Agency for approval, expected late this year. Company officials expect to have Repellex Systemic Animal Repellent on store shelves in March.
Gardeners can simply dig a few pellets into the soil around the base of the plant and, when it rains or plants are watered, the natural process of plant nutrient transfer will suck the stuff in. It will be available in tablet form at first and eventually sold in granules that can be simply shaken onto the ground around the plant.
Levar said Repellex Systemic will last three months or more, and company officials say the tests are showing full effect for an entire growing season.
"This really changes the whole (deer repellent) industry because it's inside the plant. Everything else out there was really a short-term solution that washed off and had to be re-applied repeatedly,'' said Elizabeth Summa, president of Repellex USA. "It's going to cost a little bit more (than spray-on deterrents) for a single application. But because you don't have to reapply it, it's going to be much less expensive in the long run.''
Levar notes that Repellex Systemic shouldn't be used on edible plants "unless you want your strawberries to taste like hot peppers,'' he joked. "You'd definitely be able to taste it.''
For the NRRI and University of Minnesota, Levar's research showed exactly how their applied research effort is supposed to work. NRRI scientists developed an environmentally sound concept that had possible economic potential. Repellex discovered Levar's patent as they looked for a new product line. And the University's Office for Technology Commercialization negotiated the license agreement with Repellex.
"It's worked out pretty well. I'm glad we could get it out to the public so it can do some good,'' Levar said. "And there are quite a few other applications for this as well, for getting pesticides or fungicides into plants.''