Walking through the Soybean Watch ’20 field in early August, there was a hole in the canopy about the size of a short pickup truck bed. It stopped right at a row and covered half a dozen or so of six 15-inch rows. It was a bit stop-and-start on the other side. The hole was a head-scratcher. It looked like a planter skip, but all rows didn’t skip.

After looking a bit closer, Steve Gauck came up with the answer. “It’s not a planter skip at all,” says Gauck, regional agronomy manager for Beck’s, Greensburg, Ind. Beck’s sponsors Soybean Watch ’20. “The planter did its job very well. This was caused by moles and/or voles, and maybe even field mice.”

How did they make that pattern? “They typically feed in a circular or oval-shaped area within a field,” Gauck continues. “Look closely and you can still see evidence of their runs right now. I traced out three or four just standing in the open spot.

“When soybeans were very small, they fed on them and kept feeding until the plants died. There aren’t even many weeds here. It’s good weed control from herbicides, but these critters also feed on weeds, especially once they don’t have young soybeans to feed on.”

Monitor damage

Mole and vole feeding is a problem committed no-tillers are dealing with today, Gauck says. The Soybean Watch ’20 field was no-tilled in 15-inch rows into heavy corn residue left behind by a 250-bushel-per-acre crop in 2019. These tiny critters tend to be more of a problem when there is residue on the surface.

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“Right now, there is no good control method available for them,” Gauck says. There is a bait, but it is expensive and requires careful handling.

Gauck suggests noting where these spots are within fields as you harvest and monitoring them in the future. He quips that you could mark them with GPS and then come back and make the area attractive to owls or other birds that feed on moles and voles after harvest. That’s likely not a practical solution if you have lots of acres and several spots with damage.

Other wildlife also cause damage in both soybeans and corn, Gauck notes. Raccoons and deer can impact yield on acres near woods, especially with corn. Groundhogs like to feed on young soybeans. These larger pests don’t care what type of tillage was used. When plants are tender or corn ears are in the roasting stage, they will help themselves. The damage can add up, he says.

“The take-home message here in the Soybean Watch ’20 field is that you want to determine for sure what caused stand loss if you run across it at harvest,” Gauck emphasizes. “Do some investigating. Don’t just assume it was a planter mistake and that no seed was planted. You may find, as in this case, that there are other factors at work which can affect soybean stands. Whether it’s widespread enough to cause concern on a whole-field basis is something you will need to determine for yourself.”