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How to Detect and Treat Common Lawn Pests

By Julie Bawden-Davis

When it's thick, healthy and emerald green, your lawn is one of the most inviting parts of your home landscape. But when your turf is brown and sickly due to pest invasion, it quickly loses its appeal. Learning about the various pests that threaten your grass – and then arming yourself with an effective treatment plan – will help ensure your lawn stays healthy and beautiful.

Identifying common lawn pests and the damage they cause

The best way to control lawn pests is to identify them correctly, get to know their life cycles and symptoms, and then treat them promptly and properly at optimal times.

Common signs that pests have invaded your turf include brown spots, dead and dying grass patches, wilting blades, bite marks on grass, and, of course, insects in the grass or turf layer. Signs of underground pest damage include thin or missing roots and holes in the soil.

The following pests can cause significant damage to your lawn:

Pest ID & Prevention

Grubs (beetle larvae)

Among the most damaging of all lawn pests, white grubs (Phyllophaga species) are the larvae of a wide variety of scarab beetles, including masked chafers and Japanese beetles. In the spring, summer and early fall, these plump, c-shaped larvae feast on lawn grass roots just below the soil surface.

Life cycle: White grubs that become common beetles, such as masked chafers, complete their life cycle in one year. In midsummer, adult beetles mate and the female beetles eventually lay eggs in the soil. These eggs hatch in two weeks and the new grubs soon begin feeding on grass roots. By fall, with cold weather approaching, the maturing grubs burrow several inches into the soil and go dormant for winter. As the ground warms in early spring, the white grubs make their way to the soil surface and begin feeding on grass roots again. In early summer, they stop eating and pupate, transforming into adult beetles.

Symptoms: Grub damage begins with signs of wilted grass blades, followed by brown turf patches and eventual death. Spongy, grub-damaged turf lifts easily off the soil in spring and summer to reveal grubs underneath. If you see crows, skunks or moles feeding on your lawn, they are most likely searching a grub meal.1

Chinch bug

Turf grass can be attacked by several types of chinch bugs, including the common hairy chinch bugs, which inhabit different areas of the country. Chinch bugs are sap-sucking insects that feed on grass Several types of chinch bugs attack lawn grasses, including the hairy chinch bug commonly found across a wide range of the country. Chinch bugs are sap-sucking insects that feed by sucking on grass blades. While feeding, chinch bugs secrete an anticoagulant that causes grass to stop absorbing water. As a result, the grass withers and dies.

Life cycle: Chinch bugs lay eggs in grass and produce at least two generations from spring to early fall, when the weather begins to cool. Their eggs hatch in 20 to 30 days, and the young bugs (known as nymphs) soon begin feeding on the grass. The nymphs mature in four to six weeks and then mate, repeating the cycle of life. When the weather cools in fall, adult chinch bugs seek shelter at the base of grass stems, where they remain inactive until weather warms the following spring.

Symptoms: Chinch bug damage to lawns is most visible from June to September, when the bugs are actively feeding. Irregular patches of turf first take on a purple tinge, and then wilt, yellow and turn brown. Due to the wilting and dryness of the grass, the damage is often mistaken for drought stress, but closer inspection will reveal the true culprit.2

Sod webworm

Sod webworms are the turf-damaging larvae of the sod webworm moth. The young sod webworm matures to about 1 inch in length and becomes brown or green in color with dark spotting. The dingy, gray-tan adult moth has a distinctive protrusion that looks like a double snout.

Life cycle: Sod webworms have two to three generations each year in the spring and summer. Adult webworm moths lay eggs on grass blades at night; the eggs hatch within seven days. Young webworm larvae feed at night and hide during the day in silken burrows they create in the grass. In five weeks, they transform into adult moths.

Symptoms: Sod webworms eat grass blades and entire stems, leaving brown patches behind. Their damage is swift and extensive. The turf is often riddled with holes from birds foraging for worms, and silken tunnels are found at turf level.3

Armyworm

As the name implies, armyworms do battle with your lawn. These 1- to 2-inch-long pests vary in color, from gray to yellow to pink, depending on type. Armyworms turn into brown moths that are easy to distinguish at night. As they gravitate toward light, they reveal their furry abdomens.

Life cycle: Armyworms produce two to three generations throughout the spring and summer months. The adult armyworm moths lay clusters of small, white eggs that hatch within a week. The wormlike larvae then feed for two to three weeks before turning into moths.

Symptoms: Armyworms eat grass blades and stems, and they skeletonize leaves on other plants as well. They generally take shelter from sun and heat during the day and feed most heavily on your lawn in the evening, at night, or in the early morning. As the worms eat the grass, they create circular bare spots in lawns. When invasions are heavy, the lawn appears to move.4

Cutworm

Several species of cutworms exist. Most are about 2 inches long and are gray or brown with some striping. The adult moths are a dull gray with brown or black markings.

Life cycle: Adult cutworm moths lay eggs in the spring on the tips of grass blades. The eggs hatch into worms, which feed during the night and stay hidden during the day. After feeding for two to four weeks, the worms become moths. This reproduction cycle repeats three to six times a year, depending on the region. Areas with mild winters experience more reproduction cycles.5

Symptoms: Cutworms shelter in underground burrows during the day and emerge at night to feed at the base of grass, biting stems completely off. Both the burrows and sheared-off grasses are visible on closer examination. Short grasses are often hit hardest, with damage leading to dead spots in the yard.

Effective Lawn Pest Control

Lawn pest damage often goes unnoticed and unchecked until major damage occurs. Fortunately, you can quickly and efficiently control and prevent pests such as cutworms, armyworms, sod webworms, grubs, and chinch bugs with the help of GardenTech® Sevin® brand insecticides.

Sevin® Insect Killer Granules kill more than 100 insect pests by contact, working above and below the surface. This highly effective answer to lawn pest problems won't harm plants, blooms or lawn when used as directed. Use it on fruit and vegetable gardens, ornamental and flower gardens, and around your home as well. Plus, it keeps killing insect pests and protecting for up to three months.

Sevin® Insect Killer in ready-to-use, ready-to-spray and concentrate liquid forms also treats more than 500 types of lawn and garden pests, including damaging moths and beetles. Tough on pests, but gentle on gardens, these liquid forms also work by contact and provide up to three months of continuing protection.

A pest-free lawn is a pleasant place for family and friends to gather and enjoy your outdoor spaces. Keep an eye out for these common turf nuisances and act promptly when they strike. With the help of GardenTech® brands and Sevin® garden insecticides, you can control common lawn pests and stop them in their tracks.

Total Time to Keep Lawn Pests Under Control:

45-90 minutes per week during spring and summer

Effort rating: 2 - Easy Does It

Time breakdown (depending on the number of pests detected and the size of the lawn):

  • Locating lawn pest infestation areas: 15-30 minutes
  • Applying control products: 30-60 minutes, depending on the size of the infested turf area.

Always read product labels thoroughly and follow instructions carefully, including guidelines for application frequency and pre-harvest intervals (PHI).

GardenTech is a registered trademark of Gulfstream Home and Garden, Inc.

Sevin is a registered trademark of Tessenderlo Kerley, Inc.

 

Sources:

1. Paul Heller, "White Grubs in Home Lawns," PennState College of Agricultural Sciences, May 2006.

2. David J. Shetlar and Jennifer Andon, "Chinch Bugs in Turf Grass," The Ohio State University Extension, January 2012.

3. Paul Heller, "Sod Webworms in Home Lawns," PennState College of Agricultural Sciences, January 2007.

4. "Armyworms Invade Lawns," PennState College of Agricultural Sciences, June 2012.

5. Pat Vittum, "Cutworms," University of Massachusetts Amherst, May 2011.

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