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Lawn Insects

The most common insect problem of home lawns is the white grub. Other pests associated with lawns are cutworms, sod webworms, ants and millipedes. Other pests occur less frequently.

White grubs are the larvae, or young, of the common June beetle. The large brown or black beetles are common during late May or early June. They fly against window screens in the evening hours, attracted by the artificial lights. The beetles lay eggs in grassy areas. If they lay enough eggs and enough larvae survive, the larvae feed on grass roots and damage your lawn. The grubs are usually in the soil for three seasons before emerging as adult beetles. Severe damage usually occurs the second year following a heavy flight of beetles.

You can easily lift turf damage by white grubs, as root anchoring no longer exists. Damage may start as brown patches which become evident in the lawn when there is no moisture. Increased mole, skunk and blackbirds feeding activity is another indication of white grubs.

If you have white grubs, they can be controlled by the insecticide Diazinon. Apply according to label directions.

Cutworms and sod webworms work at the soil surface, cutting off blades of grass. Small patches of injured turf, several inches in diameter, are the first indication of attack. The spots seem to increase in size each day. Look at the turf where healthy and injured areas meet. The worms should be evident along with clipped pieces of grass. Unusual blackbird activity is another indicator of worms. This can happen throughout the summer.

If you have cutworms or sod webworms, you can control with Diazinon or Sevin. Mow the lawn before treatment. Water thoroughly and then apply the insecticides as the label directs. Do not allow children or pets on the lawn until the application has dried. Avoid watering for several days after application.

Ants are primarily nuisance pests, but they can destroy new seeds, redistribute weed seeds and allow roots to dry. Diazinon, available as a two percent granular form, works well against ants.

For future reference, you may want to obtain a copy of Extension bulletin E-904, "Lawn Pests in North Dakota," which is available at your county office of the NDSU Extension Service.

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