Lawn Grub and Insect Control

Japanese beetles eat foliage and lay eggs that grow into grubs.

Lawn grubs are small, fat, white larvae of beetles. Their bodies curl into a "C" shape. If you have a lot of beetle activity in your yard in spring and early summer, your lawn may be susceptible to grubs later in the season. Beetles lay eggs in moist turf in midsummer, and grubs begin growing and feeding on grass roots by late August and September. Signs of grub infestation are brown patches in lawn, which can be confirmed by cutting up a section of brown grass to look for grubs.

Insecticides

Insecticides that kill grubs include diazinon, trichlorfon, imidacloprid and halofenozide, with brand names Dylox, Merit Intercept and GrubEx. Insecticides must be watered into the soil for successful application. Handle insecticides carefully and follow all directions for safe use and grub control. Use insecticides when grub infestation has been confirmed by visual observation after taking up sections of affected turf or as a preventive measure if adult beetles are numerous.

Nematodes

Nematodes are an organic form of grub control. Heterorhabditis bacteriophora nematodes are very small worms that invade grubs, release bacteria that kill them, and then eat the remains. Nematodes are sold by mail order and online. They are applied to lawns and watered in and work within a week. Treat only affected areas of turf, as that is where the grubs will be concentrated.

Milky Spore

Milky spore is another form of organic grub control. It is a bacteria, Bacillus popillae, which is applied to the moist lawn in warm temperatures and works within a couple of weeks. It is safe for beneficial insects, pets and humans. Established milky spore applications provide lasting protection from grubs for years.

Aerator Sandals

Aerator sandals, which strap on over shoes, have long spikes on the bottom. The wearer walks across the lawn with the sandals on, punching holes in the turf that aerate it and allow light and oxygen into the root area. A side benefit of aerating the lawn is that it kills grubs in the path of the spikes.

Other Controls

Other controls for lawn grubs include birds such as robins who feed on grubs and other worms, beetle control with beetle traps or hand picking, and good lawn maintenance, removing old leaves, sticks and plant materials and re-seeding in the spring and fall. Robins and other worm-eating birds such as thrushes and starlings scavenge in grass, picking out grubs and worms they feel moving under the soil. In spring, when beetles are active, set beetle traps or make it a habit to walk through your yard with a bucket of water and pick as many beetles as you can to drop in the water and drown. Keep the lawn clear of decaying plant material, aerate and seed and water regularly so the turf isn't distressed and more prone to bugs and diseases.

References

• "The Organic Lawn Care Manual"; Paul Boardway Tukey; 2007
• "Lawn Care for Beginners"; John Carpenter; 2010
• "John Deere Landscaping & Lawn Care"; Kristen Hampshire; 2007
• University of Illinois: White Grubs in Lawns; Bruce Spangenberg
• University of Illinois: White Grub Problems in Turf; Bruce Spangenberg
• Simple Pest Control: Grub Control; Eric Ronning