The BackYard Jungle Part XVI: Cutworms

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Here's the sixteenth in a series of articles that will help you tell friend from foe in your garden.

by Ron West

Let's imagine ahead a couple of months to early spring. It's planting time, and an enthusiastic organic gardener has just set out a beautiful assortment of tender young seedlings. Her work done, she stands back and proudly surveys the newly planted veggie patch-and sleeps soundly that night with visions of mature cabbages, tomatoes, and peppers dancing in her head.

The shock comes next morning when our hopeful backyard farmer steps out the door to admire her new garden, only to find several of her freshly transplanted seedlings lying prone and lifeless, their stems severed at or near ground level.

Cutworms.

Unlike the nibbling attacks launched by most other garden insect pests, cutworm damage-immediate and irrevocable-is fatal. to seedlings. And just one lonely cutworm can destroy several plants in a single night's foray.

Most cutworms are gray, brown, or black, sometimes with spots or stripes. They average about an inch long, tend to curl up when disturbed, and, after the better part of two summers spent in the destructive larval form, become harmless, nectar-drinking owlet moths (family Noctuidae), commonly known as millers.

For the sake of scientific convenience, the 20,000 or so species of cutworms are frequently divided according to feeding habits into four primary groups: surface feeders, tunnel makers, subterranean cutworms, and climbers.

Of the four, the surface feeders are the variety most often associated with the name cutworm, because they neatly slice through the stems of plants near ground level. Even more destructive, though, are the tunnel makers, since they often sever the stems of many more plants than they eat. Unlike the first two groups, subterranean cutworms live almost entirely below ground.

The final class of cutworms, the climbers, differ from the other three categories of Noctuidae larvae in that they inflict most of their damage, not to a plant's stem, but rather to its leaves. The most destructive variety of climbing cutworm is the armyworm, a brightly striped moth larva that often attacks gardens and farm fields in battalion strength, destroying the hard-won produce of human labor in short order.