They are found up to 150 mm below the soil surface. Life Cycle: Most grass grubs hatch in December and January and pupate 9-10 months later. Newly hatched larvae are about 5 mm long and weigh only 2-3 mg. They moult (cast their skins) three times. Insect Appearance: The larvae are C-shaped when relaxed, creamy white in color, and have a light tan head and a horseshoe-shaped cluster of anal bristles. Tall fescue supports relatively high populations of grass grub but with little effect on plant production. Symptoms: Grass grubs attack the roots of most pasture plants, but their numbers are highest under susceptible species such as white clover and ryegrass and very low under the resistant lucerne and Lotus major. More damage can be done by birds scratching at the turf to feed on the larvae.Ĭontrol: Apply insecticide in early to mid spring and apply grub control in late spring/early summer. Cutworms don’t seriously damage grass unless there is severe infestation. They mature into moths in July or August.ĭamage Threshold: If you find more than 10 larvae per square foot, it’s time to act. Larvae resume feeding early in spring (and only at night). Life Cycle: Moths lay their eggs in late summer, and after hatching, cutworm larvae overwinter in trash and clumps of grass. They can be various colors but are most often gray, brown, or black some are spotted or striped. Insect Appearance: The larvae of cutworms are plump, smooth, and almost always curl up when disturbed. Symptoms: As with armyworms, cutworms leave small, 1- to 2-inch-wide patches of brown grass in newly seeded and established lawns the plants are eaten off at soil level.

Download cutworms in lawn