How do you know if your garden problem is cutworms?
The short answer to that question is that whole stems will be cut off at the base. This is how the cutworm gets it’s name. The other part to that answer would be you won’t spot anything that could be doing the damage. It will seem to be a mystery.
Unlike many insects and worms that show up in a garden, the cutworm hides. When inspecting damaged leaves, you’ll likely see nothing. Cutworms sleep in the dirt during the day and feeds at night. Sneaky little buggers!
I noticed that something was eating my potato leaves. I was thinking “potato beetle” or slugs, and kept inspecting the plants and leaves closely. I saw nothing. Each day more leaves were eaten, and then the stalks began to fall – chewed off at the base. That clicked, because I know I’ve dealt with this before. Cutworms! Now, what is it they do? And how do I deal with them?
Organic Spray Did Not Help
I got my handy organic spray and sprayed the heck out of the plants. That didn’t seem to stop the problem one bit. I have two raised beds of potatoes and one was doing very poorly and then it began to show up in the other bed.
It was time for drastic measures. This meant researching online. Sure enough, it seemed the culprit was cutworms. I read that they overwinter in the soil and emerge in spring.
I believe I brought the cutworms into the raised beds when I added leaves from the yard as mulch. The potatoes were planted in dirt – new this year – from bags purchased at the local Home Depot, so I think the only way they could have been introduced was through the leaves and Spanish moss I added.
While researching the problem, I read that slugs will also eat potato leaves and mounding the soil around the plant will help. ( This page about slugs and potatoes is a good one for advice if you have that problem.)
I began scraping away all the leaves I had on top of the gardens and throwing it in the woods. Then I began digging up hills to mound around each of the plants. And that is when I saw it – a big cutworm! Altogether I found about 6 worms, large and small. One was greenish, one was pink and the small ones were black.
The pupae stage is when the worm / caterpillar has become a cocoon. The adult moth will emerge from this reddish orange shell to fly around and lay eggs that become more worms. But the worms are the worst in Spring – just in time for planting.
Getting Rid of Cutworms
My potato gardens are small. I have two raised beds with a total of 10 plants growing. I simply continued to dig around in the dirt searching for the worms.
The cutworms I found were placed into my tray bird feeder and within a couple of minutes a cardinal was having the worms for a meal! This is a very simple way to get rid of the worms while helping out the birds. If you don’t have a tray feeder, just set them on a board or rock in the yard where birds visit. The birds come fast for the juicy meal.
I also went out at night to inspect the plants and found one more worm which I hand picked off. I continue to check for worms but haven’t found any more.
Eggshells and Coffee Grounds
Lots of online sites have advice about getting rid of these destructive worms, but I like to do so as naturally as possible. I had a few eggshells leftover from my eggshell seed starters project, so I crunched them up and sprinkled them around the base of the remaining potato plants. The only problem with this is that the shells get moved around when watering.
Also, the worms do not like coffee grounds so you could do the same thing with leftover grounds.
Make a Collar
After checking on my potatoes, I came over to the other raised bed and one of the bean plants was totally chewed off! Just in case the cutworm was to blame, I made tin foil collars for the other plants. They have to be pushed down into the dirt and must surround the stalk.
This is best done when the plants are very young so the roots will not be disturbed. I used foil, but other things work. Think toilet paper and paper towel cardboard. Plastic cups, plastic bottles, and anything round and open will work.
Now my potato plants (in garden number 2) look like bare stalks. I’ll continue to check for worms and watch to see if the stalks come back.
Ways to Prevent Cutworm Problems
The worms emerge from eggs in Spring and they have been existing underground. Till the garden or dig down a few inches to search for the worms and remove them before planting. Take precautions by using the collars mentioned above – this is not that difficult to do if the garden is small.
Please visit this page at The Real Dirt Blog which is full of excellent information and advice about the cutworm.
Read more here about cutworm stages: adult larvae and pupa drawings.