Identifying and Stopping the Insects Destroying Maryland Lawns

A lawn turning brown in late summer gets blamed on heat almost every time, and sometimes that is exactly right. But lawn grubs Maryland homeowners deal with every fall, along with a handful of other insects, cause damage that looks a lot like drought and gets treated the wrong way as a result.

At Healthy Lawn Services, we deal with lawns affected by pests all the time. Before reaching for the hose or worrying about disease, it helps to know what pest damage actually looks like and how it differs from everything else that turns grass brown.

Is It Drought, Disease, or Something Eating the Roots?

Three different problems produce three different patterns, and the distinction matters because the fix for one does nothing for the others.

• Drought stress shows up as fairly even browning across the lawn, and it usually greens back up within a few days of consistent watering
• Disease, such as brown patch, tends to form circular or semi-circular patches rather than random shapes
• Insect damage creates irregular, patchy areas that keep spreading even after you water, because the problem is happening below the surface where irrigation cannot reach it

If you have been watering a brown patch faithfully for a week with no improvement, that is usually the clearest sign you are not dealing with drought at all.

The Tug Test: A Two-Minute Way to Check

Before assuming an insect is responsible, grab a handful of grass at the edge of a damaged patch and pull. Healthy turf resists and holds firm. Grass with root damage from grubs lifts away almost like a loose carpet, sometimes in large sections, because the roots underneath have already been chewed through. This single test rules pest damage in or out faster than almost anything else you can check yourself.

Meet the Culprits Behind Maryland’s Lawn Damage

White Grubs and the Japanese Beetle Behind Them

White grubs are the larval stage of the Japanese beetle, and they are the most common reason lawn grubs Maryland lawns lose whole sections of turf every year. Adult beetles emerge in June and July, mate, and lay eggs in the soil. Those eggs hatch into grubs that spend late summer and fall feeding on grass roots just below the surface before burrowing deeper to overwinter.

Signs of a grub problem include spongy-feeling turf, irregular brown patches, and grass that peels back easily under the tug test. Heavier infestations sometimes attract skunks or raccoons digging at night, since the grubs themselves are a food source.

Chinch Bugs in Hot, Dry Stretches

Chinch bugs feed by piercing grass blades and injecting a toxin as they draw out sap, which produces yellowing and browning that looks almost identical to drought stress. The key difference is that chinch bug damage does not respond to watering the way real drought stress does.

These pests favor the hottest, driest parts of a lawn, often near driveways, sidewalks, or south-facing slopes where reflected heat builds up.

Fall Armyworms

Fall armyworms are less predictable but capable of doing serious damage fast. These caterpillars can be identified by a distinctive inverted “Y” marking on the head, and they arrive in Maryland on storm systems moving up from the south, typically in late summer or early fall.

Maryland saw a severe outbreak in 2021. When populations are heavy, a lawn can go from green to brown in a matter of days.

Timing: Preventive vs. Curative Treatment

Getting the timing right matters as much as identifying the right pest. For white grubs, preventive treatment works best when applied in June or July, before eggs hatch, since it targets the population before any damage occurs.

If that window is missed, curative treatment in August through October is still effective, since young grubs feeding near the surface are easier to control than mature ones.

Chinch bugs and fall armyworms do not have the same preventive window. Both are best addressed with curative treatment as soon as active feeding is confirmed, since neither pest gives much advance warning before damage starts.

When It’s Worth Calling a Pro

A few situations point toward bringing in a technician rather than guessing at a store-bought product:

• More than a small section of the lawn is affected
• You are not sure whether you are looking at drought, disease, or insects
• A previous treatment did not solve the problem
• The damaged area was recently seeded through aeration and overseeding and you want to protect that investment

Misidentifying the cause wastes time and money, and by the time damage is obvious to the eye, the window for the most effective treatment may already be closing.

Protecting Your Lawn Going Forward

Grub preventative treatment is built into our Healthy Lawn Packages, timed to catch the problem before it ever reaches the surface. A well-fed lawn also recovers from pest pressure faster than a stressed one, which is part of why our lawn fertilization program works alongside pest prevention rather than as a separate concern.

If your lawn is showing signs of insect damage, send us a message and we will get a technician out to confirm what is actually happening beneath the surface.