There are over 14 specials of Cutworm commonly found in Canada. They are members of the Butterfly and Moth group of insects (Order: Lepidoptera). The larval (caterpillar) stage of cutworms causes feeding damaged to plants.
Some species of cutworm over winter as pupae (cocoon) from which adults (moths) emerge. The adults lay eggs on grass or on the soil surface from May to early June. The eggs hatch in 5-7 days producing larva (caterpillars) that feed on grass and other plants for 3-5 weeks (June/July). After feeding they pupate in the soil. A second generation of adults (moths) emerge late August to early September. Other species over-winter as eggs that hatch during early warm spring days and feed on early seedlings. They usually only have one generation per year however, a late second generation may damage crops in warm fall weather.
At night, Cutworm larva (caterpillars) feed on stems of vegetable and flower seedlings and transplants at or near ground level, severing them or completely consuming small seedlings. During the day they rest below the soil’s surface curled beside plant stems.
Cutworms in home gardens are a real challenge for the organic gardener. They are a particular problem in new gardens where turf (grass) existed previously or in weed infested gardens. The following control meters have been found effective.
- Place collars made of stiff paper, cardboard, tin cans, aluminium foil, or plastic around transplant stems at planting. Collars should be 2” high and pressed firmly into the soil.
- One week before setting out plants and at planting time, scatter moist bran mixed with Safers BTK and molasses over the soil surface. (Mix 3ml Safer’s BTK, 60ml molasses in 1L of water and add to 1L of Bran. Stir until Bran is evenly moist and apply over 4.5m2 or 50ft2)
- Dig around the base of damaged transplants in the morning and destroy caterpillars hiding below the soil surface
- Set up Transplants later in the season to avoid damage
- Keep garden weed free
- Cultivate the soil in late summer and fall to expose and destroy eggs, pupae, and larvae.