What to Do for Grubs in a Strawberry Patch?

Pest Identification

• A number of species of root weevils are drawn to strawberry plants. The dark to light brown adults are snout beetles, about 1/5 inch long. The various species differ only minimally in size and color. The beetles' larvae are white grubs, 1/4- to 1/2-inch long, with a C-shaped body. The grubs' heads are a light color and the pests are legless.

Damage

• The adult beetles do not damage plants extensively and only feed on foliage. Damaged leaves are notched at the edges. The females lay their eggs in the soil and the emerging larvae, or grubs, start to feed on the roots. The grubs create tunnels in the roots and the crown of the plants, causing stunting, weak growth and eventual death. Damage in strawberry patches is often confined to large circular areas since the adults have the habit of collecting in large groups.

Cultural Management

• Implementing cultural management strategies reduces the need for chemical control options. Start cultivating around plants during spring to expose the pupae and grubs to natural predators. To stop the spread of pests to new strawberry patches, plow under the old patches and beds as soon as possible.

Chemical Management

• Keep a lookout for the emergence of adults between late May and all through June. Start using sprays to control the adult weevils right after harvest time, before the pests get a chance to lay eggs. Recommended insecticide for adults includes cyfluthrin, lambda-cyhalothrin or bifenthrin. Spray foliage and the base of plants where adult beetles rest. Drench the soil with imidacloprid, following the instructions on the label, to control the larvae or grubs in the roots. Irrigate the site right after application.