Digger Spade, MG Plant Detective
January is generally a quiet time for the clinic crew. But some folks do garden through the winter and this client was one of those. He grows leeks and parsnips and harvests them through the winter. The parsnips, he said, benefit greatly from the cold weather and become sweeter. The leeks can usually stand the cold losing only a few of the outside leaves.His problem was that when he went to dig up some parsnips, all that was left of a few of them was the top showing a little new growth, and most of the outer layer of the root. The rest he said was gone, obviously consumed, but, he asked, by whom? And what can be done to save his parsnips?
The usual thieves in the garden are rabbits, birds, slugs, etc. But most of the underground damage to plants is caused by voles. These are pretty common in meadows and lawns with long grass, and they can be a problem for grain producers. So how did they end up in the vegetable garden? Where is this garden? In a rural setting and pretty close to a field.
Well, that’s why he has voles in his garden, but doesn’t answer his question about how to eliminate them.
First he needs to know his enemy. Voles behave like a cross between a mole and a mouse. Like moles they make tunnels and like a mouse they can come to the surface to feed. But mostly they eat roots and nice sweet carrots, and parsnips must be like vole ice cream. If there are any parsnips left, the best solution, short-term, is to harvest them and store in a cool spot in damp sand or a similar storage place.
Long-term, getting rid of the voles probably involves close mowing of the area around the garden to reduce vole territory, keeping a close eye on the garden for small holes that indicate vole activity, and probing for tunnels. Then the most effective way to reduce the vole population is to set up bait stations using warfarin baits. Voles will generally find cover such as an inverted plant tray, piece of plastic or board. So placing these around the garden will help in finding if voles are present. And keeping baits dry is important. Baits placed in a 2” T-tube can be set either in a tunnel or at ground level under a good layer of mulch. Placing the bait at the site of the purloined parsnips (having removed all that remain) would be a good place to start.
We asked him if he had any apple trees in his garden and suggested he take a close look at them because voles love all things apple, particularly the roots.
We gave the client print-outs of two links, which give directions for bait stations and describe the kind of damage that voles do.
Digger and Associates
Voles
http://whatcom.wsu.edu/ipm/manual/rasp/voles.html