Hi Leslie,

Thank you for contacting the UVM Helpline regarding your potato damage. Without a photo of the damage, it is difficult to determine the exact cause. If there are small, deep holes, it could be caused by wireworms. If the holes are larger and shallower, it could be white grubs. The following website has photos of potato damage that will help you identify the cause:

https://archive.lib.msu.edu/DMC/Ag.%20Ext.%202007-Chelsie/PDF/e965.pdf

Both wireworms and grubs will overwinter in the soil. To prevent, you may want to try altering your planting method, e.g. plant in a trench.  The following websites discuss ways to grow potatoes:

http://www.gardening.cornell.edu/homegardening/scenec6be.html

https://extension.unh.edu/blog/2020/03/what-best-way-grow-potatoes-containers

I hope this helps and happy planting!

Looks like damage is more likely from grubs.  I attach a photo.  How do I prevent/limit grub damage - or whatever might be the source?

Hi Leslie,

Thank you for sending the photo of the damage. It appears to be damage from some kind of rodent, e.g. mice or voles. These critters love to burrow through garden soil in search of potato tubers. Once found, they begin to gnaw on the potato and continue to consume the tuber until they’re satisfied.

Voles can live in colonies of hundreds of individuals and catching them in the act is difficult. They are most active during dawn and dusk and spend most of their lives underground. Mice are typically not as problematic as voles because they don’t live in large colonies. However, they love to nestle and dig under straw.

While crop rotation could help, it certainly isn’t a complete control method, especially if your garden is smaller. Voles and mice will travel a good distance to find their favorite foods.

In order to control, you may want to consider changing your growing method. Traditionally, seed potatoes are planted 9-to-12 inches apart in a 3-to-4-inch deep trench with the eye side up. They eyes are then covered with 2-to-3 inches of soil. If the soil is heavy and doesn’t drain well, the eyes should be planted more shallowly and pile soil over the tubers to create a raised bed.

The following websites discuss additional ways to grow potatoes:

http://www.gardening.cornell.edu/homegardening/scenec6be.html

https://extension.unh.edu/blog/2020/03/what-best-way-grow-potatoes-containers

Other options for controlling mice and voles are contained in the following websites, e.g. trapping.

https://www.missouribotanicalgarden.org/gardens-gardening/your-garden/help-for-the-home-gardener/advice-tips-resources/pests-and-problems/animals/voles

https://extension.psu.edu/voles

I hope this helps,

.