Cutworms
Noctuidae larvae
📖 Description
Cutworms are the larval stage of noctuid moths and are among the most frustrating pests for gardeners because they strike without warning, cutting down healthy seedlings overnight at the soil line. They are primarily active at night, spending the day coiled in the soil near the base of their host plants. A single cutworm can destroy several seedlings in one night by chewing through their stems. While most damaging to young transplants and seedlings, some species climb plants and feed on foliage and fruit. The damage is most severe in spring when gardens are full of tender young plants. Their habit of curling into a C-shape when disturbed is a key identifying characteristic.
⚠️ Symptoms to watch for
- Young seedlings cut off at soil level overnight,Stems chewed through at or just below the ground,Wilted plants lying on the ground with severed stems,No visible insect during the day,Irregular holes in leaves near the ground on older plants,C-shaped caterpillars found in soil near damaged plants
🩹 Treatment
- Place cardboard collars around transplants (3 inches above and below soil) (organic),Apply Bt (Bacillus thuringiensis) as soil drench at planting (organic),Sprinkle diatomaceous earth around plant bases (organic),Hand-pick at night with a flashlight (organic),Use bran bait treated with spinosad (organic),Apply carbaryl bait around plant bases (chemical)
🌿 Organic treatments
- Place cardboard collars around transplants (3 inches above and below soil),Apply Bt (Bacillus thuringiensis) as soil drench at planting,Sprinkle diatomaceous earth around plant bases,Hand-pick at night with a flashlight,Use bran bait treated with spinosad
🧪 Chemical treatments
- Apply carbaryl bait around plant bases
🛡️ Prevention
- Use cardboard or aluminum foil collars around transplants,Till garden soil 2-3 weeks before planting to expose and destroy pupae,Remove weeds and plant debris where cutworms hide,Plant transplants later in the season when they are larger and tougher,Use floating row covers on seedbeds and new transplants,Encourage ground beetles and tachinid flies as natural enemies
🪴 Affected plants
- Tomatoes,Peppers,Cabbage,Lettuce,Seedlings,Corn,Beans,Broccoli
🦋 Natural predators
- Birds,Ground Beetles,Parasitic Wasps,Tachinid Flies
🌱 Host plants
- Various seedlings,Vegetables,Flowers
🔄 Lifecycle
- Adult moths lay eggs on weeds and plant debris in late summer and fall.
- Some species overwinter as partially grown larvae, others as eggs.
- Larvae become active in spring, feeding at night on seedlings and young plants.
- They pupate in soil in early summer.
- Adults emerge in summer and lay eggs for the next generation.
- One to two generations per year in most regions.
- Adults are strong fliers and attracted to lights.
📅 Season
- Spring to Early Summer (most damaging to seedlings)
🔎 Appearance
- Smooth, hairless caterpillars that curl into a C-shape when disturbed.
- Colors range from gray and brown to greenish-black.
- Some species have spots or stripes.
- Active at night, hiding in soil during the day.
💥 Damage level
- High
🔁 Reproduction rate
- Fast
🗺️ Geographic regions
- North America
- Europe
- Asia
- Africa
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