Have you been wondering what those 1- to 2-inch holes in your field are lawn are from? Well, more than likely, they're caused by prairie voles. No, not moles, I'm talking about voles with a v as in Victor. They're reddish-brown to gray and larger than a field mouse, but smaller than a rat. They're torpedo-shaped bodies are about 4 to 5 inches long with very short tails.
With conservation tillage and set-aside acreage on the increase, these critters have really built-up their populations the last few years across NE Missouri. Why all the fuss!? Because prairie voles, unlike moles, are primarily vegetarians and they like corn and soybean seed and seelings, not to mention clover. Dense prairie vole populations can reduce plant stands by 80-100%.
In order to thrive, prairie voles require 2 things: cover and food. Prairie voles prefer a full canopy cover for protection from predators. Grass and legume fields, field borders, wheat or rye stubble, set-aside, CRP fields, and cover crops seedlings all provide an ideal habitat for very high vole populations. I've also seen prairie vole colonies in lawns where there's less cover, especially around homes near row crops.
Prairie voles build a network of 1- to 2-inch-wide runways. In no-till fields, the runways are usually aboveground under the thick mulch cover. But, in other areas with less canopy or ground cover such as lawns, voles will dig underground runways. All runways connect to shallow, mounded underground burrows. When they are actively in use, these mounded burrows usually are the home of at least one pair of adult voles and their young. However, one colony can have many adults.
Prairie voles can eat a variety of different things, but prefer forage and roots from succulent grasses and legumes. Established stands of alfalfa, clovers and other legumes often develop high vole populations. Feed grains such as corn and wheat are also high on the list of preferred foods. The feeding range of an active vole colony can range from about 100 square feet to a 1/4 of an acre.
Fields should be scouted prior to planting for prairie vole colonies. They can often be identified by looking for dark green, high spots caused by vole urine and feces. The presence of fresh clippings and/or fresh feces next to a slick, open hole is a sure sign of vole activity. If 5 or more active vole colonies per acre are identified, damage control should be planned.
Damage in no-till field corn usually occurs during the first 21 to 28 days after planting. The prairie vole will dig into the planter slot to eat the germinating seed and small seedlings. Once the corn kernel is decayed or the plant reaches about 8 to 10 inches tall, feeding damage usually stops.
Prairie vole populations can be reduced by removing food and cover; or by applying a rodenticide. Tillage, low mowing, and application of early pre-plant herbicides are all methods for removing food and cover. As of last year, 2% zinc phosphide pellets can now be used to kill prairie voles. However, since zinc phosphide is a restricted pesticide and extremely toxic to wildlife, it must be used in-furrow.
Another method for reducing prairie vole damage in no-till fields is to provide an alternative food source prior to planting. Research conducted by the University of Illinois indicated that 4 pounds of cracked corn per acre successfully reduced vole damage in no-till corn.
If you would like more information about prairie voles or how to get rid of them, please give me a call at (573) 769-4137. Till next time, this is Jimmy Smith, your Area Agronomist, with University Extension in Palmyra.