Lawn Pest Control for Manatee and Sarasota County Lawns

How to Tell What Is Eating Your Lawn

A dying patch in a Florida lawn has a short list of likely causes, and each one needs a different treatment applied at a different time. Treating for the wrong insect does not just waste an application, it wastes the window when the right treatment would have worked.

Here is how to narrow it down before you call anyone.

Start with a simple question: does the grass die, or does it look chewed? Chinch bugs and grubs kill the plant, so the area goes brown and stays brown no matter how much you water it. Sod webworms and armyworms eat the blade and leave the plant alive, so the lawn looks ragged and scalped rather than dead. That one distinction rules out half the list.

Chinch Bugs

Southern chinch bugs are the leading cause of St. Augustine grass loss in Manatee and Sarasota counties, and they are the first thing we check on any brown patch.

They are small, about an eighth of an inch, black with white wing patches, and they cluster at the edge of the damaged area rather than in the dead center. They feed by piercing the blade and injecting a toxin, so the grass dies rather than being chewed.

Where to look: the hottest, driest, sunniest part of the lawn. Along a driveway, next to a sidewalk, against a south-facing wall, anywhere reflected heat builds up. They almost never start in the shade.

What it looks like: an irregular yellow to straw-brown area that expands outward and does not recover after watering. The grass at the edge is yellowing while the center is already dead.

When: they are active most of the year here and peak in the heat, but populations that survive fall are what start next spring's damage, which is why fall treatment matters more than most people realize.

Mole Crickets

Mole crickets are the Bahia grass problem, though they will work St. Augustine and Zoysia too. They tunnel just below the surface, feeding on roots and separating the grass from the soil as they go.

Where to look: open sunny turf, often the front lawn and the strip near the street. They prefer sandy soil, which describes most of this county.

What it looks like: the surface feels spongy underfoot and the grass thins without an obvious pattern. You will see small raised tunnels like miniature mole runs, and loose soil pushed up at the surface. Damage often looks worse in the morning, since they tunnel at night.

The soap flush test: mix two tablespoons of dish soap into two gallons of water and pour it over a two-foot square of suspicious turf. Mole crickets come to the surface within two or three minutes. More than two or three in that square means a treatable population.

When: timing is the whole game with mole crickets. They are far easier to control as small nymphs in early summer than as adults. Fall treatment targets the adults before they overwinter and lay next year's eggs.

Tropical Sod Webworms

This is the fall problem, and it moves fast. The caterpillars feed at night from late summer through November and can noticeably thin a lawn in about a week.

Where to look: anywhere, but damage often appears first in the shadier, more humid parts of the lawn.

What it looks like: the lawn looks like someone mowed it too short in patches. The blades are notched and chewed on the edges rather than dead. The plant survives. Look for small green pellets of frass down at the soil line, and for small tan moths flying up in a zigzag when you walk the lawn at dusk. The moths do not feed. They are laying.

When: September through November is the peak in this area, which is exactly when most homeowners stop watching the lawn.

Fall Armyworms

Armyworms get their name from how they move. They arrive in numbers and advance across a lawn in a front, so the damage looks like a line moving through the grass rather than a patch appearing in one place.

Where to look: they start wherever the moths landed, often the edge of the lawn nearest open ground or a field, then work inward.

What it looks like: the lawn appears to be shrinking from one side. Look closely at the blades in the advancing edge and you will see them chewed down to the stem. Birds working an area hard is a reliable tell, because they are eating the caterpillars.

When: late summer into fall, and they move fast. An armyworm front can cross a lawn in a matter of days, which is why this is one of the few lawn pests worth treating the same week you spot it rather than at the next scheduled visit.

Call us if you think you have them. We would rather come out and tell you it is something else than arrive a week later.

White Grubs

Grubs are beetle larvae living in the soil, feeding on roots. They are the other cause of grass that lifts away with no resistance, which is why they get confused with mole crickets.

Where to look: anywhere, though damage often shows first in sunnier areas where the turf is already under stress.

What it looks like: irregular brown patches that do not respond to watering, and turf that peels back like carpet when you pull it. Dig two or three inches into the soil at the edge of the damage and you will find C-shaped white larvae if they are the cause. More than five or six in a square foot is a treatable population.

The other tell is what else shows up. Armadillos rooting through the lawn at night and leaving the ground turned over are usually digging for grubs. If you have an armadillo problem, you very likely have a grub problem underneath it.

When: treatment works best on young grubs feeding near the surface. Older grubs go deeper and are much harder to reach, which is another reason timing matters more than product.

The Pull Test: A Two Minute Way to Narrow It Down

Grab a handful of grass at the edge of the damaged area, where the yellowing meets the green, and pull straight up with steady pressure.

If it holds firm, the roots are intact. The problem is above ground: chinch bugs, disease or drought stress.

If it lifts away like a loose piece of carpet with no root resistance, something has eaten the roots. That is grubs or mole crickets.

Now look at what came up. Chewed and notched blades with the plant still alive means caterpillars, so sod webworms or armyworms. Blades that are dead but intact means chinch bugs or disease. Rotted blade bases that pull apart easily means fungus rather than insects.

This will not give you a definitive answer, but it will tell you which half of the list you are in, and it will tell you whether the problem is urgent. If the grass lifts away in sheets, it is urgent.