Potato Problems


I’VE BEEN LOSING TWO OR THREE POTATO STEMS A DAY. Something has been chewing them off below the dirt line where I’ve mounded soil around the plants. All in all, I’ve lost about eight stems over three days. If this keeps up, I worry that I’ll have serious potato problems.

The good news is that the damage has been confined to one section of potatoes and the potatoes themselves don’t seem to have been damaged. The bad news is that damage has been inflicted on both plants in pots and in the ground, so that likely rules out voles. They are bad at climbing and won’t crawl into a pot to get at the plants.

Voles would have been my first guess at what was causing my potato problems. But it could also be mice, insects or some kind of disease. I’m not sure. Another point of evidence is that today I just found a beet plant that also had been chewed off just below dirt level. The small beet root had bite marks in it and had cleanly been separated from the rest of the root.

Glycoalkaloids are toxic

My understanding is that potato stems are toxic due to glycoalkaloids. If people or animals eat stems they probably will have a burning sensation in their mouth and become very sick. That’s why I’m surprised that something is causing this problem.

Glycoalkaloids give potatoes their flavor, but green potatoes have too much and will make people sick. You should NEVER eat a green potato or even cut off the green part and eat the rest. The green is just an indicator that the potato has too much glycoalkaloids in the entire potato.Potato Problems

Clearly some bugs are immune to glycoalkaloids because I see cucumber beetles and other unidentified bugs eating the potato plant leaves all the time.

Cooperative Extension Ask the Expert service

I’ve asked the University of Vermont Cooperative Extension service what could be causing my potato problems. I’ve also sent pictures. In my article Organic Gardeners: You Are Not Alone there’s a link for the Cooperative Extension Ask the Expert service where they answer questions about plant growing problems.

Extension Educator Alice Mullen responded to the request and said it is either voles or cutworms. I know I have both in the garden, but after considering the information provided by the Extension Service, my guess is cutworms. The photo of the severed potato stem in the cutworm link looks very much like my severed potato stems. Plus, some of the potato stems that were severed were in a pot, which seems to rule out voles.

On the other hand, the beet seems to have been eaten by a vole. The link to the vole information mentions beets as a primary target and the bite marks at different angles are characteristic of voles.

Unfortunately, my options for defense against cutworms are limited. At this stage, I can’t put any type of protective barrier around the stems. There are just too many stems. I have to hope that the stems get big enough before too many get hit. By mounding up the dirt to the point where the stems are small enough for cutworms to do their thing, I’ve created an environment where they can cause damage even to well-established potatoes.

Are you having the same potato problem as me? Better yet, have you had the same problem and resolved it. Let us know by commenting below.

Related articles:

1. Organic Gardeners: You Are Not Alone
2. Scallions Are Still Onions
3. Book Review: Eliot Coleman’s Four-Season Harvest

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15 Responses to “Potato Problems”

  1. July 8, 2011 at 8:00 pm #

    I have never had Cutworms,would’nt know one if i saw one.On the other hand,i have had trouble with voles,as i live in the country.This does not sound to me like voles as they seem to do most of their damage underground.Last year they nibbled on some of my potato’s,but again that was underground.You don’t find out until you dig up the potato’s,each one has a piece eaten out of them.They will make their home underneath the potato’s if they are allowed to.Also,last year they made a home under my beats.I did not find out until i was harvesting them,the hole ran all the way along the row just under the beats.They ate the bottom half of the beats just under the ground,about 20 or so beats were damaged.When i reached the end of the hole i caught 2 adults and 5 young at the end,i don’t have to tell you what happened to them.If you are not sure what it is,set a mouse trap for them,if it is a vole you will catch it.Put a piece of apple on the trap,they love things that are sweet,that why they like the beats.I have mouse traps at the ready this year.Good luck.

    • July 8, 2011 at 9:45 pm #

      Bob — I’ve got so many voles I’m not sure I could have an impact with a few mouse traps. I may have to try is they start eating my beets.

  2. July 9, 2011 at 8:01 pm #

    Perhaps it is time to get a young cat? Mine has been going to town on the voles or gophers (not sure what they are).

    • July 10, 2011 at 8:18 am #

      Amy — We have a one-year-old cat but don’t let him out of the house. We have a lot of wild animinals (cayote and fox mostly) that eat cats regularly. The neighbor’s cat does spend a lot of time in our garden and I found a dead vole two days ago that looks like it was killed a cat. The good news is the cutworms have stopped for now. I think it is because the potato vines have grown big enough to prevent cut worm damage.

  3. Cathy
    July 9, 2011 at 8:25 pm #

    Bill, my first thoughts when I read your post were voles and cutworms. The best remedy for the voles is either a cat or a small dog. Our cat kept them in check until she died and then most inexplicably, one of our little Cavalier King Charles Spaniels took up where she left off. Cut worms are often the grubs of Japanese beetles and bt can help with that. I wish you luck. It is so frustrating to have the food chewed out from under you!

    • July 10, 2011 at 8:26 am #

      One good thing is the voles eat the Japanese beetle grubs, so I’m hoping that we will have fewer beetles this year. I’m pretty sure that cutworms and Japanese beetle grubs are a completely different insect. See cutworms

      • Cathy
        July 10, 2011 at 10:33 am #

        Cutworms and JB grubs are different but since they often cause the same kinds of issues in the vegetable or ornamental garden, they are sometimes confused.

        I would caution you not to underestimate the problems voles can cause. The few Japanese beetle grubs they eat are the ones that are in their way as they burrow through your garden.

        The first year after our cat died, between the voles and a gopher, our entire vegetable garden was chopped down to the dirt and we lost nearly all of our clematis and 50% of our perennials — nearly 1/4 acre of damage in one season.

        Voles do not hibernate and they will try to get into your house, garage, automobiles, and outbuildings to nest. They can be very destructive, ruining cushions for lawn furniture, canvas umbrellas, anything that they can use to make a nest. Left to their own devices, they are rampant breeders.

        We were very limited in our options because we have fish and small dogs and toxicants posed a serious risk to them. We’d also had an invasion into the house over the winter, a major headache that was finally effectively dealt with by an exterminator.

        Fortunately, one of the little dogs decided he had had enough (or decided he was really a cat, we aren’t quite sure) and he went after them in the yard. In one month he killed 26 of them along with 3 gophers who were trying to burrow into the yard.

        We consulted our local Fish and Game Dept. for guidance. They told us that once the wildlife outside of our fenced in yard realized that inside the fence was inhospitable, they would communicate that to each other and we would see the numbers dramatically decrease. We found that to be the case. Our little guy did a fabulous job of controlling the problem and scaring away even more of their kind.

        Good luck with all of it! It can definitely be very challenging. It has taken two years for our perennial beds to recover, but they are doing well.

        • July 11, 2011 at 7:57 am #

          Thanks for providing the details on your situation with voles. I was very surprised to learn that your dog could be so effective in keeping the population down.

          • Cathy
            July 11, 2011 at 9:59 am #

            Bill, I think one of the reasons he is so successful is because of the fence, which keeps him and his siblings in and the larger wildlife (coyotes, fishercats, and deer) out. And the other is because he barks at them – he has a very low, fierce sounding bark and that in and of itself serves to warn them off. He will stand at the fence and bark at the gophers, rabbits, and chipmunks and we watch them head off in another direction. They take him seriously.

            The Fish and Game officer told us that a dog who is a good “ratter” (he mentioned Jack Russells specifically) and a fence are the best non-chemical means of control. He said that wild animals do communicate risks to each other and once they identified this area as a risk we would see a sharp decline, and we have.

            Our dogs are Cavalier King Charles Spaniels and although they aren’t well known for their “ratting” ability (they are promoted more for their gentle personality and companion dog and lap dog reputation) according to our breeder they rival the rat terrier as an effective means of pest control. We never knew that until after we experienced it and mentioned it to her.

            This little guy learned his craft from the cat – while she was alive, they were best buds. But he is much more efficient than she was and I think that it’s because of the barking.

            There is still the occasional vole, rabbit or chipmunk who manages to get under or through the fence but he and the others are off like a shot after it, and most of the time, they get back on their own side of the fence very quickly. If not, they become the appetizer of the day.

            You might think about acquiring a rat terrier or Jack Russell, especially if you plan to keep your cat indoors (which is not a bad idea, actually). Even better if you can locate one who has been raised on a farm and exposed to other dogs hunting voles and such.

            I do think that often times they need someone to teach them how to be effective hunters. Now that the other three have seen this little guy at work, they ll join in the fray when he is on the hunt, but until he and the cat bonded, I don’t think he would have known instinctively what to do to catch his prey.

            Like most people facing a rodent problem on a farm or agricultural setting, I immediately think CAT. I would never have thought of a dog! But this neurologically impaired little dog also took out three gophers who burrowed under the chicken wire that we buried down into the ground from the lower edge of the fence — even enlisting the aid of a sibling to get one that was larger than he is. When the two of them dragged it to our patio door, barely alive and still twitching, I almost fainted dead away. Fortunately, that is one of the last ones who was brave enough to come inside the yard.

            Good luck with it. As I mentioned earlier, the grubs and cutworms did a modest amount of damage but the wildlife totally destroyed our entire vegetable garden in a very small amount of time… literally almost overnight. It was VERY disheartening to have nurtured it all spring and just as we were starting to get vegetables nearing harvest, it was decimated. Farmer’s markets are okay but there is nothing like homegrown.

          • July 11, 2011 at 11:35 am #

            You’re right, there’s nothing like your own homegrown.

  4. July 10, 2011 at 10:06 am #

    Thanks for the information on cutworms,i had never seen them before.I think our long and cold Winter keep a lot of grubs and bugs away.Also,we have King Birds that visit us every year and nest here.Their main food is moths and bugs.i see them sitting on the wire that is round my raspberry’s every morning feeding.

  5. Cathy
    July 10, 2011 at 10:45 am #

    Bill, I was just reading through earlier replies… the reason that the cutworm damage has stopped is because they are really true cutworms. They stop feeding mid June. One problem solved!

    Good luck with the voles.

    • July 11, 2011 at 7:59 am #

      Everything has been late this year, so it is likely that the cutworm season may have been late this year, too.

  6. July 18, 2011 at 11:43 am #

    Hi Bill, I’m happy for you that your problem has disappeared for now. I’ve never had cutworms, though my potatoes get blight every year. At last you have time to research before you plant potatoes again.

    Have you begun to harvest yet? I dug up one row. My harvest this year is better than previously, but that’s not saying much! Anyway, I’m off to cook the potatoes I dug up yesterday. They will be lovely with butter and fresh mint.

    • July 18, 2011 at 7:26 pm #

      Hi Alison — I haven’t started to harvest potatoes yet. My leaves have not yet even started to die back. I’m about three-fourths of the way to maturity. The banana fingerlings I planted take about 150 days and I’m at about 90 days. Hope you thoroughly enjoy your potatoes.

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