Anyone who has spent time planting and caring for an outdoor vegetable garden has likely encountered the dreaded pest the cutworm. Though very common, and potentially quite devastating, there are numerous methods for controlling and curtailing the presence of cutworms in your garden. We will discuss the best methods here.
Cutworms are found worldwide, and are actually the larvae (or caterpillars) of numerous species of night flying moths from the Noctuide family. They were given the moniker “cutworm” because of their voracious appetite and subsequently, their ability to cut down young plants as they feed at the stem or below the surface. Typically, a young cutworm will begin feeding on the first part of a plant they encounter (usually the stem) and devour until the stem is felled or cut in half. Some cutworms will cut off a plant from underneath the soil, causing the rest of the plant to shrivel and die. Though some cutworms will remain eating the remaining fallen plant, most often the cutworm will move on to another stem rather quickly, thus causing a rather disproportionate amount of damage to crops when compared to the actual size of the pest or infestation.
Identification of cutworms:
Cutworms may vary in appearance, ranging in color from tan or green to even pink, gray or black, yet most often appear green, brown or gray. Like the moth they will eventually morph into, cutworms, may appear uniform in color, or spotted and striped. They are a soft bodied caterpillar, most often dull or greasy in appearance, (though they may appear in more bright and vivid forms as well). At it greatest length, a cut worm will reach up to two inches (40 mm) in length, and are most readily identified for their characteristic of curling into a “C” when disturbed.
In many climates, cutworms will winter just under the soil (typically within 1-2 inches of the surface) either as a final instar larvae, or as a pupae.
Damage caused by cutworms:
As mentioned above, because of its feeding habits, the cutworm is especially deadly for young crops.
Cutworms feed on a variety of plants, including asparagus, beans, cabbage, kale, rutabaga and other crucifers, as well as corn, celery, lettuce, peas, peppers, and tomatoes. Some species even feed on turfgrass.
Adult moths are nocturnal and will lay their eggs on vegetation, or on moist ground surrounding plants, and the cut worm caterpillar larvae will hatch anywhere from 3-24 days after being laid and begin feeding almost immediately on vegetation near the ground. After 10-14 days, the larvae will become noctural feeders, staying underground during the day, and feeding only at night.
Methods of control:
There are several methods that can be utilized to control cutworm populations or to effectively eliminate their threat to ones crop.
1. Tilling: In some climates, as mentioned above, cutworms will winter under the soil. If this is the case, a farmer may control the pests by winter plowing or tilling. (or by tilling the soil 2-3 weeks before planting). Most farming sources recommend deep plowing or tilling in the fall, and again in early spring.
A winter plow will kill many of the cutworms in either the pupae/larvae or instar state, or bring them to the surface where they become subject to predators (chickens, moles, shrews, blackbirds, wasps, and parasitic nematodes). This method works exceptionally well for grain fields. (We utilize this method in our garden, and our chickens absolutely love this time of year, often spending hours eating the caterpillars that are turned over by the tiller).
2. Starvation and good weeding practices: Another less commonly used method of controlling cutworm populations is that of starving the caterpillars. If it is practical to keep weeds at a minimum before your planting and growing season, you can discourage cutworm moths from laying their eggs where your plants will be growing, and also depriving what larvae are present, the food they will need to grow. Along with this idea, many farmers make efforts to remove plant residue in their gardens, to reduce egg-laying sites.
3. Baits and poison: Secondary to successful starvation strategies, baits can also be utilized rather successfully. This is done by following up starvation methods with providing a sweetened bran mash containing a suitable stomach poison against the cutworm. Remember to use very small amounts, too crumbly and thinly scattered to be ingested by domestic animals or desirable wildlife.
4. Plant Collars or barriers: Perhaps the most widely known treatment for cutworms is the use of plant collars. This should be done right at the time of transplanting. It is a bit time consuming, but definitely works. You can use aluminum foil, plastic soda bottles, tuna fish cans, or a cardboard collar around the plant stem approximately 4 inches tall. The collar should fully encircle the the plant stem, and be pressed at least an inch deep into the soil. This creates a barrier to keep cutworm larvae from feeding on plants. Some growers use toilet paper or paper towel tubes cut at 3 inch intervals filled with potting soil, and standing in a tray for planting seeds, and when the seeds have matured sufficient for transplanting, plant them together, with the tube, in your garden.
5. Hand picking: Nothing beats an excuse to roll up your sleeves and get on your hands and knees in the garden, and the existence of cutworms is a great excuse. It is best to go looking for cut worms at night, or in early evening, with a flashlight while they are out and actively feeding. You will find the cutworms on the stems and foliage of your plants eating away. Simply pluck them off of the plant, and crush them, or drop them into a bucket of soapy water. Personally, we place them in a ziplock or sealable bag and feed them to our chickens the next day.
6. Capsaicin sprays and powders, extracts of pineapple weed or sagebrush: There are various organic treatments that are recommended for use against cutworms, including sprays or powders made from either ground red pepper (cayanne) or red pepper spray. These types of sprays are recommended by “Rodale’s Ultimate Encyclopedia of Organic Gradening” as a repellent for numerous garden pests, including the cutworm. To repel cutworms, it is suggested that cayanne pepper be dusted around the base of the plant stems. It is also suggested by numerous sources, that coffee grounds, extracts of pineapple weed, and sagebrush may act as a deterrent to the cutworm larvae.
7. Oak leaves, vulcanite sand, damp wood ash, egg shells, or diatomaceous earth: Some folks choose to mulch their plants with oak leaves, vulcanite sand, damp wood ash, egg shells, or diatomaceous earth to deter cutworms. These components may act as irritating physical barriers against the cut worm larvae. Personally, we do not use diatomaceous earth because we also raise bees, and some studies suggest that diatomaceous earth can be harmful to bees.
8. Bacillus Thuringiensis: Bacillus thuringiensis (Bt) is a naturally occurring soil borne bacteria that is widely available and has been used since the 1950’s for caterpillar and insect control. It can be applied via spray to young plants, (and in other ways), and is a very effective control against climbing cutworms or stem eaters. Beware however that Bacillus thuringiensis is also harmful to butterflies, which are powerful and important pollinators.
9. Cornmeal: Another effective method for killing cutworms is sprinkling cornmeal around your plants. Though we have not tried this in our own garden, it is reported by the farmers almanac and other sources that the cutworm larvae will eat the cornmeal but not be able to digest it, thus causing them to bloat and die.
As you can see, there are many methods to combat the cutworm, and good reasons to do so. Though there are a large variety of garden pests that can affect the growth of your garden or crop, most (like the cutworm) can be combated rather easily. Do not let the presence of cutworms deter you from growing fantastic plants. You will likely find out that deterrents for one pest may also deter others. For more information regarding garden pests, you may wish to research 1. common garden pests, 2. beneficial insects for gardens, and 3. organic treatment for garden pests.
