Contrary to popular belief, insects are not a common cause of residential lawn damage in Modesto. Many insects in the lawn are beneficial. Never apply an insecticide unless a damaging level of a known insect pest is confirmed.

How to know if insects are causing damage:

• Brown spots in lawns can be caused by over or under watering, plant disease, and improper use of chemicals or dog urine as well as insects.
• Confirm the presence of insects before applying an insecticide. For grubs, dig around roots, for other insects perform a drench test.
• For instructions, call the UC Cooperative Extension Office (209) 525-6800 or go to UC Davis Pestnotes.

Keep your lawn healthy by:

• Planting grass species that do well in you area.
• Watering deeply and infrequently.
• Doing routine maintenance on sprinkler heads.
• Applying only three to six pounds of actual nitrogen per 1000 sq. ft. each year when fertilizing.
• Aerating your lawn annually; remove thatch if it exceeds 1/2 inch.
• Cutting only 1/3 to 1/2 of grass height at each mowing and keeping lawnmower blades sharp.

If your lawn is damaged:

• Find out which insecticide ingredients target specific lawn insects then choose the right product for your pest.
• Bacillus thuringiensis (Bt) kills only caterpillars, including cutworms, lawn moths and skippers.
• Some nematodes control caterpillars or grubs.
• Azadirachtin controls cutworms, armyworms, and larvae of lawn moths.
• Imidacloprid is effective against young lawn grubs.
• Acephate and permethrin are broadly toxic pesticides that kill cinch bugs, lawn moths, and cutworms, but also kill beneficial insects.

www.ipm.ucdavis.edu, IPM Introduction, resources, ants, aphids, cockroaches, termites, tree borers, fleas

For more specific information on lawn insects visit the UC Davis website.

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