JUNE
1992

 

 

 

By
Tom Turpin
 
Professor of
Entomology
Purdue University

 

 

 

 

 

06-12-92

Cutworms Everywhere

Gardeners hate them, and farmers live in fear of them.  They are cutworms, larvae of moths that are named after their habit of cutting plants as they feed.

There are many species of cutworms, and their numbers vary greatly from year to year.

Some cutworms are described in terms of their lifestyles.  There are climbing cutworms, solitary cutworms, army cutworms and subterranean cutworms.  Some cutworm names are descriptive of their appearance, such as spotted, black, dingy, yellow-striped, white, glassy, or bronzed cutworms.  But generally, cutworm moths are rather nondescript, drab-colored insects.  The moths are normally grey and brown with a few distinct markings.

Most cutworms spend the winter in the larval stage in temperate regions.  In the spring, the larvae pupate and emerge as moths, which then lay eggs in areas of vegetation.  There, newly hatched larvae begin to feed on the closest plants.

One of the most widespread cutworms is the black cutworm, which is found worldwide.  In the heartland of the United States, the black cutworm is a seasonal invader. Moths migrate into the area each spring from areas of the Gulf Coast and lay eggs in early season weeds or even crop debris.

When a new crop is planted, the hungry larvae begin to feed on those plants.  These young larvae feed on foliage for a week or so, then their feeding habits change.  Black cutworms larvae become light-sensitive and go underground.  The insect, which is now termed a subterranean cutworm, emerges from its soil hideaway during the nighttime hours to feast upon tender stems of all like plants.

If the target of cutworm feeding just happens to be a gardener, an irresistible force has met a self-proclaimed immovable object.  The gardener cherishes each plant.  The cutworm looks at all the plants as mere food items and proceeds to do what is does best:  eat!   What's more, the cutworm adds insult to injury by cutting more plants than it really needs for a food supply.  Much to the dismay of the gardener, this results in dead and damaged plants, so chemical warfare begins.

It's a timeless battle between cutworm and gardener, and one thing is for sure:  gardeners will, at some time, get caught with their plants down!

 

Writer: Tom Turpin
Editor: Carol McGrew