How to Identify Cutworms
Cutworms are common on a wide variety of vegetables and any fresh seedlings. To identify them, try patrolling your garden in dusk and evening hours, when cutworms will begin to feed. They are also partial to cloudy days.
Different species range in color from grey to pink, green and black and can be as long as two inches. They can be solid, spotted, or striped. They tend be curled up when they are not on the move. Cutworms are stealthy, and tend to feed only at night, while hiding in daylight hours.
Black cutworms, also known as Agrotis ipsilon, are some of the most common cutworms. They have small dark spots on their bodies and mature into the dark sword-grass moth. Variegated cutworms, another common species, are mottled brown and have a faint white stripe down their backs.
Adult cutworms are moths of dark wing colors. They are usually brown or gray, and they are about 1 ½ inches long with a 1 ½-inch wing length. You should keep an eye out for them, because the females will lay eggs in dry soil after they mate.
Photo Credit: GrowVeg.com/gailhampshire on Flickr Creative Commons. The adult moth of the brown cutworm is an indicator that cutworm eggs could be in your soil.
Cutworms chew through plant stems at the base. They primarily feed on roots and foliage of young plants, and will even cut off the plant from underneath the soil. In most cases, entire plants will be destroyed; they do a lot of damage in no time at all. Even if only the bottom of the plant is destroyed, the top will often shrivel and die.
In the summer, cutworms sometimes crawl to the tops of plants and do damage there. Be careful not to mistake this damage for slug damage.
Photo Credit: John Obermeyer, Purdue University. Black cutworms can cause severe injury to the base of plants, often killing them.