When herbicides shifted and glyphosate became top dog, suddenly there were weeds popping through that we hadn't seen before, One by one, farmers and weed control specialists figured out how to address them. The same thing happened when farmers went to no-till and used different herbicides that weren't incorporated.
And it's apparently happening again as more farmers get serious about using cover crops to prevent soil erosion over the winter protect water quality, plus loosen the soil for spring planting. Barry Fisher, state resource conservation specialist for the Natural Resources Conservation Service, fielded plenty of questions about how to control voles, a tiny varmint that resembles a mole, during the annual no-till breakfast in southeast Indiana last week.
"They tend to show up where it's grain later into the spring," Fisher says. "Since annual ryegrass is one of the preferred cover crops, we've been hearing reports that it's attracting some voles. One option is to be sure to spray the cover crop and get 14 to 15 days of die-down before you plant.
"Another option is to turn to cover crops that provide protection aboveground and whose roots still provide protection belowground, but which naturally don't make it through the winter. Oats and forage radishes are possibilities. They are dead by spring anyway. Dead vegetation doesn't seem to attract the rodent pests."
There is a bait available for control, zinc phosphide, but most specialists agree it ought to be reserved for only severe infestations or instances where you know there is a den of the animals that you can wipe out by using this material. Another suggested option is to spread a bushel of cracked corn per acre on the surface so that the voles will feed on that instead of corn seed that you've just no-tilled.
One farmer questioned whether one of the new vertical tillage tools that operate around two inches deep would help limit or even control such a problem if it was run before the field was planted in the spring. While evidence is only anecdotal, in theory it makes sense.
"This pest is a vertical creature," says Dave Osborn, Ripley County extension ag educator. "Their burrows are four to five inches deep. Whatever you do that shortens their burrows ought to help in controlling them."