Are Chinch Bugs Eating My Lawn?

If you notice mysterious yellow patches of grass that turn brown and die rather than perk back up with regular watering, you may have a chinch bug problem. Unlike other types of turf grass pests, chinch bugs must reach a high population density before you notice anything amiss. Once they begin to flourish, however, they can devastate an entire lawn in just weeks.

“Surprisingly, your lawn can host quite a few chinch bugs without causing noticeable damage,” says agronomist Bob Mann, director of state and local government relations for the National Association of Landscape Professionals. “It’s only when conditions favor an explosion in population that they become problematic.”

Chinch bugs are found in most states and all types of turf grass. “Chinch bugs are infamous for causing damage to lawns all across North America,” says Drew Wagner, chief technical officer of Sod Solutions. “Often a chinch bug infestation is confused with a water drought issue, however.”

Early detection of a chinch bug infestation is key to avoiding expensive lawn repair or turf replacement. Here’s what you need to know.

What Are Chinch Bugs?

Chinch bugs are minuscule insects that live at the base of your turf grass, near the soil. They change in appearance over their lifecycle, beginning as bright orange microscopic nymphs and maturing into dark adult bugs that measure less than 1/4-inch long.

Although hard to spot with the naked eye, Mann says chinch bugs are most recognizable as adults. “They are black in color, about the size of a sharpened pencil lead and sport a white hourglass-shaped mark on their backs,” he says. “They scurry over the surface of a lawn very quickly when disturbed.”

Types of Chinch Bugs

According to Wagner, the types of chinch bugs homeowners most often encounter are:

• The common chinch bug: Normally found from Connecticut westward to Ohio and south as far as mid-Texas across to mid-Georgia;

• The hairy chinch bug: Cohabits some of the northern range of the common chinch bug but is also found throughout the northeastern states;

• The southern chinch bug: Most common type found throughout the southeast;

• The western chinch bug: Found in the western states from Oklahoma and Texas to California.

Signs of Chinch Bugs

Chinch bug damage looks like drought damage, so you may have a hard time identifying signs of an infestation. One main difference is that dry yellow and brown patches of grass suffering from lack of moisture generally spring back to life when watered, whereas dead patches of grass due to chinch bugs do not.

“Detection becomes difficult during drought conditions when lawns naturally go into dormancy and turn brown,” Mann says. “Chinch bug infestations can go undetected only to reveal themselves when temperatures cool, rains return and healthy grass begins growing again.”

The best way to determining a chinch bug problem is hands-on observation. Mann advises getting on your hands and knees and looking closely at the lawn, especially the warm, sunny areas when browning and thinning of the turf occurs during midsummer.

Otherwise, Wagner recommends conducting a float test. “Take an empty coffee or other large metal can and remove the top and bottom with a can opener,” he says. “Stick the can three inches deep into the soil and add water until it is about three-quarters full. Let the can sit for 10 minutes and then stir the water to agitate the contents and see if any chinch bugs float to the top.”

How Do Chinch Bugs Impact the Lawn?

Chinch bugs feed on the surface of your grass rather than in the thatch or the soil. They damage your lawn in two ways.

“These pests have chewing/sucking mouth parts that allow them to bore into the stems of turf grass plants in order to feed on the sap within, drawing off water and nutrients and making the plants weaker,” Mann says. “In sucking sap from the plants, they inject saliva back into the plants. That saliva is toxic and will cause plant death.”

Chinch bugs inflict the most damage during the nymph stage of their life cycle, and are the most active from late June to early September.

“Although the chinch bug life span of seven to eight weeks is relatively short, it allows for up to five generations of chinch bugs throughout the summer if you live in the hotter regions of the country,” Wagner says. All those generations feeding on your lawn means that devastating infestation can develop relatively quickly.

How to Get Rid of Chinch Bugs

When your lawn’s chinch bug population hits critical mass of about 20 bugs per square foot, you need to intervene. Here are a few suggestions for ridding your lawn of chinch bugs:

• Encourage insect predators. “There are natural predators, such as Big Eyed Bug (Geocoris) and ground beetles that help keep populations low, and homeowners should consider them when contemplating treatments,” Mann says. Many insecticides kill chinch bugs and these predators, which can lead to a chinch bug resurgence in the future.

• Overseeding with special “endophyte enhanced” seeds. Endophytes are a type of fungi that live between the cells of the grasses that grow from these enhanced seeds. They provide a natural defense against chinch bugs.

• Insecticide application. “There are a number of granular or liquid broad-spectrum insecticides you can apply on your lawn to treat for chinch bugs,” Wagner says. “Look for ingredients like trichlorfon (the most powerful and only suitable for extreme infestations), bifenthrin (the most recommended for homeowner use) and carbaryl.” Always read the label carefully and follow the application directions to the letter.

• Chemical-free alternatives. To avoid pesticides, try spraying soapy water on your lawn or sprinkling affected areas with diatomaceous earth (DE), such as this one from The Home Depot. Both can be effective against a limited infestation.

How to Prevent Chinch Bugs from Coming Back

There are four lawn management best practices that will keep chinch bugs from turning up in your lawn again:

1. Ample watering. Chinch bugs prefer hot, dry conditions, so irrigate your lawn at least one inch a week during arid periods.

2. Chinch bug-resistant turf grass. “Perennial ryegrass, fine fescues and tall fescues are highly resistant to chinch bugs,” Wagner says.

3. Dethatching. Chinch bugs overwinter in the thatch layer of your lawn, so dethatch your lawn regularly to destroy hibernation sites or locations where eggs and nymphs may live.
4. Keep grass long. Mow your lawn to about 2-1/2-inches to reduce stress on the grass.