Tuesday, June 16, 2009

Cutworms

by Maggie Montgomery, Master Squisher

Cutworms. I hate them - and I’m someone who hates to hate anything!

The cutworms have been rampant in my garden for the last two years, attacking the tender, young plants. Cutworms can topple hopeful rows of young onions or carrots, beets or spinach, leaving short, dead stubble in their wake. They eat at night, hide out under the soil surface by day, and are especially active during cool, wet spring weather. They are fairly small when young, but lately I’ve seen some an inch and a half long.

I find them near newly-beheaded plants. I dig around with my fingers, sifting the soil. Digging, sifting…sometimes I find the worm, and sometimes not. When I do, I calmly and smugly squish the thing to death between two rocks, or with my gloved fingers, or between a rock and a stick. Once this year I found half a dozen large cutworms in one row of young onions! Only half the onions are still alive, but it could have been worse!

Most people protect bedding plants from cutworms by wrapping the stems with aluminum foil, or cutting the bottom out of a paper cup or part of a milk carton, burying the bottom under the soil, and planting inside the protective barrier. It is not true that the worm wraps itself around a stem to cut it. Cutworms chew through plants, so putting nails or other partial barriers near plants might not help.

Row crops are hard to protect. Besides obsessively hunting cutworms in the morning, we’ve tried sprinkling the rows with crushed eggshells and diatomaceous earth. The eggshells didn’t work at all. The diatomaceous earth only works on dry ground. The “earth” feels soft, but is actually made of tiny sharp skeletal remains of sea creatures. When the worms crawl over it, it cuts their bodies and dehydrates them. It’s not a pretty thought. There are problems keeping diatomaceous earth dry, but I think it works a little bit.

I’ve recently researched cutworm control. Cutworms are the larvae of moths that lay their eggs in grassy areas. To limit their population in the long term, we have to keep weeds and vegetation out of the garden. We have to till the soil in the fall, and again in the spring. I should surround the garden with mulched flowerbeds, or install walkways to keep the grass away from the edges. If we expand the garden into a grassy or weedy area, there will be more cutworms in the new space. The worst cutworm infestations generally occur where grassy areas have recently been broken up to create a new bed. Some garden professionals recommend treating affected areas with Bacillus thuringiensis var. kurstaki. Btk is a naturally occurring bacterial insecticide specific to caterpillars but harmless to humans and the cutworm’s natural enemies. I have never used it. Yet.

This sounds like a lot of work, but we’ll try it in the hope that it will save a lot of cutworm hunting and seed replanting in the future. If we can get this set up and make it part of our gardening routine, the onions should survive better next year!

1 comment:

Peder H said...

In one night, they killed 30 chili pepper plants that we had grown from seeds since March. I may have cried a little bit when I discovered the devastation. Then I proceeded to unleash a species specific revenge plot, the likes of which have never been seen before. I must have killed a thousand by now. Personally, I like to pull off their heads and then feed them to my chickens. Watching them die makes me feel a little better.
We replaced the peppers with some we found at a greenhouse closeout sale. We wrapped the stems in foil, put cans around the base and they have been safe so far. Someone else told us about the BTK stuff, which we haven't been able to find, so I can't vouch for it. We opted for a not so organic (gasp) poison powder that is supposed to be effective against cutworms. So far, so good.