U of M announces scientific development gardeners will like — if it works

To understand why my neighbors and Facebook friends will cheer this news, you’d have to eavesdrop on our conversations:

“Grrrrr! Is it legal to fire a pellet gun in Minneapolis?”

“Why would you do that?”

“Those @#V%$ varmints are destroying my garden. They’re relentless.”

“Have you tried trapping and relocating them?”

“What’s the point? More of the buggers move in.”

Varmints definitely have had the upper hand — or paw/hoof, if you will — in our yards.

Now, though, the University of Minnesota has announced a scientific development that gardeners will hail. If it works, that is. We will be the ultimate judges, based on trial bouts with our backyard combatants.

The news is that scientist Thomas Levar at the U of M Duluth has developed an animal repellent that works from the inside of plants by delivering a natural hot-pepper concentrate through their roots, making the plants inedible for deer, mice, voles, rabbits and other animals.

Levar, a forestry and horticulture specialist at UMD’s Natural Resources Research Institute, had learned how Dimethyl sulfoxide (DMSO) was used in veterinary and sports medicine to open pores in a membrane and move medicines through skin.

He adapted the process to plants, developing a formulation to move different types of protective chemicals through easily accessible plant pores. He started with a bitter substance that is used to keep children from sucking their thumb and moved on to capsicum, which comes from the plants that give us chili peppers. 

Capsicum is “very safe and very effective,” Levar said in a statement. And the plants are not genetically modified in any way.

In fact, many of my neighbors have tried a variation of this trick by concocting hot pepper sprays for their gardens.

The root deliver system lasts longer than spray repellents, Levar said.

Eventually, though, the plant will outgrow the treatment. In response to my email question, Levar said the systemic repellant is effective for about three months on small, young plants during the growing season. 

There are other limitations. Levar said he does not recommend this systemic repellent for vegetables and other plants you plan to eat.

“The active ingredient is dispersed throughout the tissue of the plant, therefore affecting the taste of the crop,” Levar said.

As for my mature shrubs that rabbits chomp every winter, Levar also said, “I cannot state with any certainty that large plants would be protected…that this technology will provide overwintering protection.”

Michigan-based Repellex USA has licensed the technology from the U of M and has developed tablets for use in nurseries and gardens. Place the tablets near the roots of a plant, add water, and the hot pepper concentrate is released.

“We did a lot of testing, mostly with tree growers in nurseries where they have a huge problem with mice eating away at their plants,” Elizabeth Summa, president of Repellex USA, said in a statement. “We think professional growers and homeowners will find value in planting two tablets with their trees and not having to worry about their investment.”

If the EPA approves the treatment, it could be available to commercial growers and shipped to retailers in time for the spring planting season.

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