Control cutworms biologically
Cutworms are larvae of butterfly owls living in the soil. These are inconspicuous gray moth species that belong to the family of owl butterflies (lat. Noctuidae). This family is the largest within the butterflies (lat. Lepidoptera). The cutworms are 3-5 cm long, green, gray or brown with dark head capsule.
The owls fly from mid-May, and the cutworms appear from about June. The hatched young caterpillars live on the surface, the older stages come to the surface only at night to feed. They then feed almost continuously and can cause considerable damage. When touched, the cutworms curl up in a spiral. Infestations are heaviest in light soils and dry conditions.
Life cycle of the cutworm
There are 4 stages of development: Egg, caterpillar, pupa, moth.
Eggs are laid on plant leaves in small groups or rows. The hatched caterpillars overwinter and pupate the next spring, some species in a homespun cocoon. The pupae do not feed or move. The new moths develop in them. Some species form several generations per year.
Damage caused by cutworms
Adult moths do not cause damage, but their caterpillars cause severe damage to numerous crops when they are abundant. With their biting, chewing mouthparts, the cutworms feed on plant roots or destroy young plants.
Typical damage patterns caused by cutworms are plant parts of young plants bitten off just above the ground, feeding holes on leaves, feeding damage on rootlets, rhizomes, stems and leaves, pit-shaped feeding spots on root vegetables.
What plants are attacked by cutworms?
Cutworms attack mainly lettuce, carrots, cabbage, potatoes and in the lawn.
Control cutworms with beneficial nematodes
Nematodes are tiny, filamentous soil organisms about 0.6 mm long. They are natural counterparts of many insect larvae and live in the upper soil layers. The nematode species Steinernema carpocapsae specializes in, among other things, cutworms and can use them for its own feeding and reproduction. The nematodes are supplied alive in a powder. For application, they should be mixed with water exactly according to package directions and applied to affected areas.
What stages of the cutworms can I control?
As soon as the first cutworms are detected, the nematodes can be applied.