Long days, warm nights, and afternoon rain make South Florida summers great for growing grass. Unfortunately, they’re just as great for the insects that want to eat it. From late spring through early fall, lawn pests hit their most active and destructive stretch of the year. A deep-green lawn in May can turn into a patchwork of yellow and brown by July if a pest population goes unnoticed for even a couple of weeks.
What makes it tricky is that pest damage often looks like something else. Drought stress, fungus, and nutrient problems can all leave brown patches that look a lot like an insect infestation. Knowing what the most common summer culprits look like, and the signs each one leaves behind, is usually the difference between a quick, targeted fix and a full re-sod. Here are the pests that do the most damage to Florida lawns each summer, how to spot them, and how to keep them under control.
Southern Chinch Bugs: The No. 1 Threat to St. Augustine Lawns
If you have a St. Augustine lawn, and most South Florida homeowners do, the southern chinch bug is the pest to watch most closely. These insects cause more turf damage in Florida than any other pest, and Floratam and other St. Augustine varieties are exactly what they’re after.
Chinch bugs are tiny. Adults are about a fifth of an inch long, with black bodies and white wings folded across their backs in a distinctive X or hourglass pattern. The young nymphs are even smaller and range from bright orange-red with a pale band to nearly black as they grow up. They feed by piercing grass blades and sucking out the juices while injecting a toxin that keeps the plant from moving water, which is why the damage looks so much like drought.
Signs of damage: Irregular patches of yellowing grass that fade to straw-brown and spread outward, usually starting in the hottest, sunniest, driest parts of the lawn or along sidewalk and driveway edges where heat radiates. If you water and the “dry” spots don’t bounce back, chinch bugs are a likely suspect.
How to confirm: Get down on your hands and knees at the border between green and browning grass, because that’s where the live bugs are, and part the blades near the soil. Watch for fast-moving insects scurrying around the thatch. There’s more on identification and treatment in our full guide to chinch bugs.
What to do: Chinch bugs are known for developing resistance to insecticides, so rotating between different active ingredients matters, and blanket-spraying the whole lawn on a schedule usually causes more problems than it solves. Treat the damaged area plus a buffer of healthy grass around it, keep the lawn properly watered since drought-stressed turf is far more vulnerable, and go easy on the nitrogen, which only fuels their numbers.
Tropical Sod Webworms: Ragged Blades and Evening Moths
Tropical sod webworms are the caterpillar stage of small, dull brown moths, and they’re one of the most common summer pests once the rainy season sets in. The moths themselves don’t harm your lawn, but they lay the eggs that become hungry, night-feeding caterpillars.
The larvae are small green caterpillars, often curled into a C-shape, that hide in the thatch during the day and come out to feed after dark. Because they chew grass blades rather than suck them dry, the damage has a look all its own.
Signs of damage: Ragged, notched blade edges, short chewed-down patches that look like someone spot-mowed the lawn unevenly, and general thinning that lets the ground show through. Newly installed sod and freshly fertilized, lush grass are especially appealing to them.
How to confirm: Walk across your lawn at dusk. If you see small brown or gray moths fluttering up in a zig-zag and dropping quickly back into the grass, you probably have a breeding population. We dig into this in moths flying around your lawn, a sign of sod webworms, and in our overview of sod webworms in South Florida.
What to do: Since the caterpillars feed at night, evening treatments work best. Targeted products are very effective when you catch the population early, and keeping thatch under control takes away the daytime hiding spots they rely on.
Fall Armyworms: Fast-Moving and Destructive
Don’t let the name fool you. Fall armyworms show up throughout the warm months in Florida, not just in fall. They get their name from the way they move across a lawn in large numbers, almost like a marching army, and they can chew a healthy patch of grass down to the ground practically overnight.
Up close, the caterpillars are easy to spot by the pale, upside-down “Y” on the front of their dark heads and the stripes running down their bodies. They feed most heavily in the morning and evening and can build to big numbers before you even notice them.
Signs of damage: Sudden, fast-spreading brown or bare areas, ragged and skeletonized blades, and an advancing edge of damage that seems to move day by day. Bermuda lawns are a favorite, but armyworms will attack most turf types once their numbers climb.
What to do: Speed matters here. Because armyworms can do so much damage so quickly, early detection and prompt treatment are essential. Scout regularly through the summer, and don’t wait to act if you see the population growing. Our guide to spring and early-season lawn pests covers how to get ahead of caterpillar problems before they explode.
Mole Crickets: Damage From Below
Mole crickets are one of the few summer pests that damage your lawn from underground. They tunnel just below the surface, feeding on grass roots and loosening the turf as they go. Bahia and bermuda lawns are the most vulnerable, though mole crickets will tunnel through other grass types too.
Adults are odd-looking, tan-brown insects roughly one to one-and-a-half inches long, with shovel-like front legs built for digging. They fly and mate in spring, and the nymphs that hatch do their heaviest feeding through the summer.
Signs of damage: Spongy, loose soil that gives underfoot, raised snake-like tunnel ridges across the surface, and irregular brown, thinning areas where the roots have been cut. You may also see small mounds of pushed-up soil.
How to confirm: Mix a couple of tablespoons of liquid dish soap into a gallon of water and pour it over a two-foot-square section of suspected damage. If mole crickets are present, the soap irritates them and they’ll come to the surface within a few minutes.
What to do: Timing is everything with mole crickets. Treatments are far more effective against young nymphs in early to mid-summer than against tough, established adults later on. A consistent, professionally managed treatment schedule keeps their numbers from building in the first place.
White Grubs: Roots Under Attack
White grubs are the larvae of various scarab beetles, and like mole crickets they do their damage below the surface by feeding on grass roots. They’re plump, C-shaped, cream-colored larvae with brown heads, usually found a few inches down in the soil.
Signs of damage: Irregular brown patches that feel spongy underfoot, and the classic giveaway, grass that lifts up like a loose carpet because the roots holding it down have been eaten. You might also notice secondary damage from raccoons, armadillos, or birds tearing up the turf to get at the grubs.
What to do: Grub control comes down to timing. Preventive products applied earlier in the season stop the young larvae before they cause damage, while curative products are used to knock down an infestation that’s already active. We cover exactly when to act in the best time to treat for grubs in South Florida, and we compare the two main control ingredients in our breakdown of chlorantraniliprole vs. trichlorfon for grub control.
Two-Lined Spittlebugs: Look for the Foam
Two-lined spittlebugs love the humidity and thatch of a South Florida summer. The young ones give them away: they surround themselves in a frothy, white, spit-like mass while they feed on grass at the soil line. The adults are black with two orange or red stripes across their wings.
Signs of damage: Foamy spittle masses low in the grass and around the thatch, along with grass blades that develop yellow, white, or purple streaks and eventually wilt. Damage tends to be worst in lawns with heavy thatch that stays consistently moist.
What to do: Because spittlebugs thrive in thatch and moisture, good cultural habits go a long way. Dethatch when needed, water deeply but less often, and mow at the right height. Sticking to the recommended mowing heights for Florida turfgrasses helps cut down the moist, sheltered conditions they favor.
Fire Ants and Other Summer Nuisances
Not every summer pest eats your grass. Red imported fire ants build unsightly mounds across lawns during the warm, rainy months, and their aggressive stings make them a real safety concern for kids and pets. Their mounds also get in the way of mowing and can damage equipment. Fire ants are best handled with targeted baits rather than by disturbing the mound directly, which just scatters the colony.
Summer humidity also brings out fleas and ticks, which shelter in tall or overgrown grass and hitch a ride on pets and family members. Keeping the lawn mowed, edged, and free of excess thatch removes a lot of the habitat these pests depend on.
Is It Really a Pest? Ruling Out Look-Alikes
Before you reach for an insecticide, it’s worth making sure pests are actually the cause. Summer brings several problems that produce similar-looking brown patches. Drought and heat stress can scorch grass in the same sunny spots chinch bugs prefer, but stressed grass usually greens back up after a good watering, while pest-damaged grass won’t. Fungal diseases, which thrive in the same warm, wet weather, tend to form more circular patches, sometimes with distinct margins or a ringed look, and they call for a very different response. If you’re seeing spreading brown areas and aren’t sure what’s behind them, our fungus control resources can help you tell disease from insect damage.
The quick field tests above, parting the grass at the damage line for chinch bugs, the soap flush for mole crickets, the dusk walk for sod webworm moths, are the fastest way to confirm what you’re actually dealing with before spending money on the wrong treatment.
Preventing Summer Pests Before They Start
The best defense against every pest on this list is a thick, healthy, well-maintained lawn. Dense turf resists invasion, bounces back faster from feeding damage, and gives pests fewer bare, stressed areas to move into. A few habits make the biggest difference:
- Water deeply but infrequently. Shallow, daily watering keeps the surface moist, which is exactly what many pests and diseases want. Deep, less-frequent watering builds stronger roots and a more resilient lawn. Our summer lawn care guide walks through how to drought-proof your grass.
- Don’t over-fertilize. Too much nitrogen produces lush, tender growth that pests like chinch bugs and sod webworms feed on eagerly. Follow a sensible, seasonally appropriate program instead of pushing constant fast growth.
- Mow at the right height. Cutting too short stresses the lawn and thins the canopy. The right mowing height shades the soil, crowds out weeds, and keeps grass vigorous.
- Manage thatch. A thick thatch layer gives sod webworms, spittlebugs, and other pests a place to hide and breed. Keeping it in check takes that shelter away.
- Scout regularly. Walk your lawn once a week during summer and look closely at any area that seems off-color. Catching a population early makes every treatment more effective and less expensive.
Most of these practices fall under integrated pest management, an approach that combines healthy cultural habits, regular monitoring, and targeted treatments only when they’re actually needed, rather than spraying on a fixed calendar. It’s the most effective and most environmentally responsible way to keep pests in check. And if you’re installing new sod this summer, that fresh grass is especially vulnerable while it roots, so it’s worth reviewing the best insecticide options for new sod.
When to Call a Professional
A small, early-stage pest problem is often something you can manage on your own. But some situations really do call for professional help: damage that keeps spreading despite your best efforts, pests that have built up resistance to over-the-counter products, an infestation across a large area, or just plain uncertainty about what you’re looking at. Misdiagnosing the problem, or applying the wrong product at the wrong time, wastes money and can make the damage worse.
At Floridist, we help South Florida homeowners keep their lawns healthy through every stage of the summer pest season, from diagnosis to a treatment plan built around your specific grass and property. Take a look at our lawn treatment services or get in touch for an assessment. Catching pests early, and building a lawn strong enough to shrug them off, is always easier and cheaper than recovering from a full-blown infestation.