Lawn & Turf Tips: Cutworms

Cutworms

Cutworms are caterpillars; the larvae of nocturnal moths. They measure about 1" - 2" in length and are dull gray, brown, or black. Some may be striped or spotted. They are called cut worms because of the way they cut down young plants as the feed. You can find them active just under the soil surface and will curl into a ball if disturbed (not to be confused with white grubs, or Japanese beetle grubs, which are C-shaped). Cutworms feed at night and will not generally be observed on plants or on the soil surface during the day. There are several different types known as surface, climbing, army or subterranean.

Life Cycle

• Most of the moth mate and lay eggs in the late fall on the stems of grass and weeds. There are some, however, that lay their eggs on the bare ground.
• The eggs typically hatch within a few days to two weeks.
• Most species of cutworm live under the soils surface and come out to feed at night.
• The partly grown or full grown cutworm winters over in the soil. Their abundance and development is largely dependent on the weather and rainfall.
• They continue feeding and growing until early summer.
• Then they pupate in the soil and emerge one to eight weeks later as full grown moths.
• Typically, there is only one generation per year.

Damage

There are many different species of cutworms. They all have one thing in common; they feed on plants by chewing. However, they vary as the amount of damage the do and to the host plants they prefer. They tend to destroy more of the plant than they actually eat.

Surface Cutworms cut off the young plants right at the base of the plants or slightly above the soil line. Because the most of the plant is not eaten, they attack and fell new plants nightly.
The climbing species climb the stem of threes, shrubs, vines and crops eating the leaves, buds, and fruit of the plant.
Army cutworms tend to occur in greater number and consume the tops of plants then march on to the next lawn.

Treatment

First you want to determine if cutworms are present. You can do this by looking for signs of freshly cut plants.

• Cultural treatment: At night, you can also take a flashlight and search the base of the plant and the top layer of soil. If you find them, you can hand pick them and either squash them or throw them in a bucket of water. Since the adult female moths lay their eggs in the fall, you can remove your weeds and mow the grass closer to the ground. This will aid in preventing a cutworm infestation.
• Chemical control: If you have an infestation of cutworm, a treatment of insecticide will be more effective in getting rid of them.  Depending on the severity of the infestation, it may take more than one application to get rid of them.

If you suspect you have a problem with cutworm, please call us and we will come out to identify them and treat them when they are active.