Asparagus: Cutworms and armyworms

Biology

Cutworms and armyworms are the larvae of noctuid moths. These common moths are medium-sized with fairly dull coloration. The gray to tan caterpillars are hairless, nocturnal, and generally spotted, striped, or otherwise marked. They may be 1/4″ to 1″ in length and tend to curl up when disturbed. Cutworms may climb up and feed on the growing spears of asparagus. They also eat through stems of asparagus and many other plants, cutting them off at ground level. While armyworms typically feed during the day, cutworms spend the day just beneath the soil surface or under debris near the host. They usually feed at night, so it is advisable to search for them with a flashlight in the dark. Weeds are their primary food source.

Management Options

Use Integrated Pest Management (IPM) for successful plant problem management.

Non-chemical Management

Select non-chemical management options as your first choice!

• Control weeds and grasses in and near the garden.
• Remove debris around plants that provides shelter for cutworms.
• Hand-pick night-feeding larvae, when practical. Scratch soil at the base of damaged plants to find larvae in the daytime.
• Encourage natural enemies of cutworms including birds and spiders.

Chemical Management

IMPORTANT: Visit Home and Garden Fact Sheets for more information on using pesticides.

• Apply when damage first appears.

Approved Pesticides

Listed below are examples of pesticides that are legal in Washington. Always read and follow all label directions.

• Bonide Pyrethrin Garden Insect Spray Concentrate
  Active ingredient: pyrethrins [EPA registration number: 4-371]
• Bug Buster-O [Organic]
  Active ingredient: pyrethrins [EPA registration number: 1021-1771-54705]
• Safer Brand BioNEEM Multi-Purpose Insecticide and Repellent Concentrate [Organic]
  Active ingredient: azadirachtin [EPA registration number: 70051-6-42697]
• This list may not include all products registered for this use.

Additional Images