August is one of the most stressful months for the turf and landscapes your crews are working in every day.
Late summer brings a specific set of pest pressures – insects and turf problems that peak during heat and drought, then linger into fall if they’re not caught early. The good news: most of them are manageable if you know what to look for. This month, we’re walking through the pests most likely to affect your work this time of year – and what to do about them.
PART ONE: LATE-SUMMER PESTS AFFECTING LANDSCAPERS
Think of late-summer pests like uninvited guests who show up when the party is winding down and the host is already tired. They’re harder to deal with when you’re already stretched thin – which is exactly why knowing them in advance matters.
Japanese Beetle
Japanese beetles are one of the most widespread and damaging landscape pests in West Virginia, and late summer is when their cumulative damage becomes most visible. Adults feed on the foliage, flowers, and fruit of more than 300 plant species – skeletonizing leaves and moving from plant to plant in groups.
What to look for:
- Lacy, skeletonized leaves on ornamentals, roses, and trees
- Clusters of metallic green and copper-colored beetles feeding on foliage
- Damage concentrated at the top of plants and spreading downward
Management: Hand-removal works for small infestations. For larger populations, insecticide applications targeting adults can protect high-value plants. Avoid Japanese beetle traps – research consistently shows they attract more beetles than they capture and can worsen nearby plant damage.
WVU Extension resource: Japanese Beetle – extension.wvu.edu/lawn-gardening-pests/pests
Fall Webworm
If you’re noticing large silken webs wrapping the branch tips of trees across your job sites, fall webworm is likely the culprit. Unlike the eastern tent caterpillar – which builds webs in spring in branch forks – fall webworm builds loose, expanding webs around branch ends in late summer and early fall.
What to look for:
- Loose, tent-like webs enclosing the ends of branches – not the forks
- Defoliation and browning within the web as larvae feed
- Webs that grow larger over time as the colony expands
Management: For webs within reach, pruning and removing the infested branch is the most effective approach. Bacillus thuringiensis (Bt) and many synthetic insecticides are effective against the larvae. Because fall webworm feeds late in the season on well-established trees, damage is often more cosmetic than harmful – but clients will notice it.
WVU Extension resource: Fall Webworm – extension.wvu.edu/lawn-gardening-pests/pests/fall-webworm
Spider Mites
Hot, dry summers are spider mite season – and August in West Virginia can deliver exactly those conditions. Spider mites are not insects but arachnids, and they’re small enough to go unnoticed until plant damage is already severe. They thrive in dusty, dry conditions and populations can explode rapidly during heat stress.
What to look for:
- Fine webbing on the undersides of leaves and between branches
- Stippled, bronzed, or yellowing foliage – especially on conifers, junipers, and ornamentals
- Tiny moving dots on the undersides of leaves (use a hand lens if needed)
Management: A strong water spray can dislodge mite colonies from plants. Miticides or insecticidal soap are effective for heavier infestations. Many common insecticides do not control mites and can actually worsen the problem by eliminating natural predators.
Stink Bug (Brown Marmorated Stink Bug)
As summer winds toward fall, stink bugs begin to move toward structures in search of overwintering sites – which means they’ll increasingly show up on job sites, on plant material, and around clients’ homes and buildings. While not a direct turf pest, stink bugs damage ornamental plants and fruit trees and become a significant nuisance pest as the season transitions.
What to look for:
- Shield-shaped, mottled brown bugs on plant material, siding, and window frames
- Characteristic odor when disturbed or crushed – avoid crushing them near structures
- Puncture damage and cat-facing on fruit and ornamental plants
Management: Seal entry points around structures before the fall aggregation begins. For landscape plants, targeted insecticide applications may be warranted on high-value specimens. WVU Extension notes that stink bugs can enter structures through gaps as small as 1/16 inch.
WVU Extension resource: Stink Bug – extension.wvu.edu/lawn-gardening-pests/pests
PART TWO: TURF-SPECIFIC ISSUES DURING LATE SUMMER
Turf in late summer is like an athlete finishing a hard race – it’s been under heat stress for months, and its defenses are down. That’s when pest pressure and disease hit hardest.
White Grubs
White grubs are the larvae of scarab beetles – including Japanese beetles, masked chafers, May beetles, and several other species common in West Virginia. They feed below the soil surface on grass roots, and late summer is when their damage becomes most visible as newly hatched grubs grow and feeding intensifies.
What to look for:
- Irregular patches of wilting, yellowing, or dead turf that appear in late summer
- Turf that feels spongy underfoot or can be peeled back like a loose carpet – a hallmark sign of grub feeding
- Increased bird, skunk, or raccoon activity digging into the lawn in search of grubs
- White, C-shaped larvae visible in the top 2-3 inches of soil when sod is pulled back
Management: Curative insecticide applications in late summer (August through September) can be effective against younger grubs still near the soil surface. Products containing trichlorfon or carbaryl are typically used for curative treatment. Preventative treatments applied earlier in the season (mid-June to July) using chlorantraniliprole, clothianidin, imidacloprid, or thiamethoxam are generally more effective. Biological controls including insect-parasitic nematodes are also available, though their effectiveness varies with soil moisture and temperature.
Important note from WVU Extension: Wet periods during July and early August favor survival of grub eggs. Limiting irrigation during this window can help reduce grub populations. Once eggs have hatched in late August through September, increased moisture can actually encourage grass root regrowth and reduce visible damage.
WVU Extension resource: White Grubs – extension.wvu.edu/lawn-gardening-pests/pests/white-grub
Sod Webworm
Sod webworms are the larvae of lawn moths – small, buff-colored moths you may notice flying in a zigzag pattern over turf at dusk. The larvae live in the thatch layer and feed on grass blades at night, creating irregular patches of closely cropped or browning turf.
What to look for:
- Irregular brown patches in the lawn, often appearing scalped or ragged
- Small, silken tubes in the thatch layer at the base of the grass
- Green pellets (frass) in the thatch – a reliable sign of active feeding
- Small buff-colored moths disturbed when walking across the lawn
Management: Insecticide applications in the evening – when larvae are actively feeding – are most effective. Products containing Bt, spinosad, or synthetic pyrethroids are commonly used. Thatch management and proper irrigation help reduce favorable habitat for webworm populations.
Summer Patch and Other Fungal Diseases
Late summer heat and humidity create ideal conditions for turf diseases, particularly in stressed or improperly maintained lawns. Summer patch is one of the most damaging fungal diseases affecting cool-season grasses in West Virginia, causing circular or irregular patches of dead grass that can expand rapidly during hot weather.
What to look for:
- Circular or crescent-shaped patches of yellowing or straw-colored turf
- Affected areas that may have a frog-eye pattern – green grass in the center, dead ring around it
- Damage concentrated in areas with compacted soil, heavy thatch, or poor drainage
- Symptoms that worsen during periods of high heat and humidity
Management: Cultural practices are the first line of defense – raise mowing height, reduce thatch, improve drainage, and avoid excess nitrogen fertilization in summer. Fungicide applications can help protect turf in high-risk areas, but timing is critical. Applications should begin before symptoms appear in areas with a history of summer patch.
Heat and Drought Stress
It bears repeating: many of the turf problems that look like pest damage in late summer are actually heat and drought stress – or a combination of stress and pest pressure working together. Stressed turf is more susceptible to every pest and disease on this list.
Signs of heat and drought stress that may mimic pest damage:
- Turf that turns bluish-gray or footprints that remain visible after walking across it (early drought stress)
- Dormant, straw-colored turf that recovers when moisture returns
- Damage concentrated in areas with south-facing slopes, compacted soil, or poor water retention
Management: Deep, infrequent watering (1 to 1.5 inches per week, applied in early morning) encourages deep root development and reduces disease pressure. Allowing cool-season turf to go dormant during extreme heat is a natural and often appropriate response – most healthy turf will recover when temperatures moderate in fall.
WVU Extension resource: Tips to Avoid Lawn Problems – extension.wvu.edu/lawn-gardening-pests/lawn/tips-to-avoid-lawn-problems
WVU EXTENSION RESOURCES
WVU Extension offers some of the most comprehensive pest and turf management guidance available for West Virginia conditions. If you encounter a problem that doesn’t match what you’re seeing in the field, your local county Extension office is the best first call for positive identification and treatment recommendations.
→ Insect Pest Management: extension.wvu.edu/lawn-gardening-pests/pests
→ White Grubs: extension.wvu.edu/lawn-gardening-pests/pests/white-grub
→ Fall Webworm: extension.wvu.edu/lawn-gardening-pests/pests/fall-webworm
→ Lawn Tips and Turf Management: extension.wvu.edu/lawn-gardening-pests/lawn
→ Find your county WVU Extension office: extension.wvu.edu/contact-us
THE BOTTOM LINE
Late summer is not the time to ease up on scouting. The pests and turf problems that emerge in August can compound quickly if they’re missed – especially when turf is already stressed from a long, hot season. A quick weekly walk-through of job sites with an eye toward the signs above can catch most of these issues before they become expensive problems for your clients.
When in doubt about what you’re seeing, reach out to WVU Extension. That’s exactly what they’re there for.
WVNLA is committed to keeping West Virginia’s green industry informed, safe, and growing. For questions or resources, visit wvnla.org.
