If you have paid any attention at all during the past several weeks, you have seen thousands of small, brown moths almost everywhere. They have been flying around any flowers that are blooming in the yard, around other plants, and have been attracted to any lights that were left burning during the night.

We have received dozens of calls and E-mails asking about these moths. People want to know "what are these damn moths" and "will they damage my plants." My staff and I quickly shared the necessary information with them.

Since this was an issue for so many people, I considered doing a special news release about the soybean looper moth, which is the one in question, and asking local newspapers to publish the information. But knowing the life cycle of this moth, I anticipated that by the time I could get the article published in the paper, the moths would be gone. I really expected them to essentially vanish after last Monday night when we had very heavy rainfall and the temperatures dropped drastically.

However, later in the week, the moths were still everywhere, and people were still calling asking about them. So I am using this column to tell you more about these little critters. If they are still around, you will know what is going on. If they have disappeared, you will at least know what they were.

The moths you have been seeing are the adult stage of the soybean looper caterpillar. They are also called the cabbage looper, since the favorite host plants of the caterpillars are both soybeans and cabbages. The caterpillar gets its name, because it crawls in a looping fashion. It reaches out and attaches its true legs that are located at the front of the body to the leaf of a plant. Then raises the rear of the body into a kind of loop and positions its prolegs close behind the true legs. Prolegs are appendages near the rear of the body of the caterpillar and look like legs, but they are not really legs.

For readers who want scientific information, this insect is in the family Notodontidae, species Trichoplusia. Although the caterpillar stage of this insect is easy to identify, the moth looks very much like dozens of other moths. A characteristic that helps identify the moth is a pair of tiny whitish, silvery spots spaced closely together on each forewing, almost resembling a figure eight.

Although these moths are very common in this area, we are seeing an unusually large number of them this fall. Drought conditions created an ideal environment in soybean fields, and there was an unusually large number of these "foliage" feeding caterpillars this year. Farmers actually were forced to spray their fields for caterpillars more this year than they usually do.

These caterpillars usually don't do a lot of damage to soybeans, since they only eat leaves and do not damage the soybean pods. But they can reduce soybean yields if they consume most of the leaves, which prevents the plant from capturing sunlight for the photosynthesis process. When they attack cabbages, these caterpillars can do a lot of damage, since they feed on the leaves.

Like many other moths or caterpillars, they do not overwinter this far north. The winters are too harsh for them. They live year-round and reproduce in tropical areas, including southern Florida. As spring approaches and the temperatures get warmer, the moths start heading north, laying eggs as they go. These eggs hatch, the caterpillars feed, then pupate or go through a sleep stage before developing into another moth which continues flying north. This cycle continues until they start showing up in southeastern North Carolina, which usually happens about late May.

This pattern of development is what allows us to fairly accurately predict when farmers in our area will start experiencing caterpillar problems in their crops. Georgia Love, agricultural agent on our staff, works with several farmers in the southern part of the county to monitor light traps which are designed specifically to trap migrating moths. Since the moths are attracted to light, when they start appearing in these traps, Georgia can alert farmers that the moth flights have begun and to start preparing to spray their crops if necessary.

When the moths arrive in Robeson County, they lay their eggs where the hatching caterpillars can find plenty to eat. This is usually the lush soybean fields. The eggs hatch, the caterpillars feed, go through the pupal stage, then develop into other moths, the moths lay more eggs, and the cycle starts over. We usually have about 3-4 generations of soybean loopers each year.

So what you are now seeing is the last generation of soybean looper moths for this year. The soybean fields are now mature and are not attractive feeding or egg-laying areas for the moths, so they head for your flowers. They are also attracted to lights. There must have been a zillion of them at the fairgrounds.

The moths may be feeding on nectar from flowers that are still in bloom, but they do not do any damage to plants. They may also be laying eggs, but if the eggs do hatch, the young caterpillars will probably die due to cool, damp weather and not do any damage at all. The only plants that may be damaged are fall cabbages in the garden or the ornamental cabbages that are planted in flower beds or landscapes.

So now you know the story about all these little brown moths that have been flying around and aggravating everyone. Hopefully, by the time you read this column, they will be gone for the year. You may see them again next year, but hopefully, there will not be as many of them.

E-mail address: Everett_Davis@ncsu.edu

Mailing Address:
P. O. Box 2280
Lumberton, NC 28359-2280

Phone: 910-671-3276
Fax: 910-671-6278

Date Created 10/14/02