National Snapshot

Adults on the wing, mites at their peak

Late July tips into management-and-monitoring season. The headline shift this week: spotted lanternfly nymphs are molting into their first winged adults across the Mid-Atlantic and Northeast, and they'll fly, feed on woody trees, and rain honeydew through November. Spider mites have reached their seasonal peak in the heat and deepening drought, fall webworm nests are enlarging with late-summer caterpillars close behind, and Japanese beetle is tapering in the South while still active north. A humid pattern keeps foliar disease climbing.

Invasive

Spotted lanternfly adults are emerging now and taking flight onto woody trees — tree-of-heaven, walnut, maple, birch, grape. Expect heavy honeydew, sooty mold, and the yellowjackets they attract. Scout and report new-county finds.

Caterpillar

Fall webworm nests are enlarging at branch tips, and late-summer defoliators — orange-striped oakworm and yellownecked caterpillar — are beginning. Prune small nests; tolerate light feeding on large, healthy trees.

Mite

Spider mites are at their seasonal peak — two-spotted, oak, spruce, and honeylocust mites stipple and bronze foliage, worst on dusty, drought-stressed canopies. Shake a branch over white paper to confirm.

Sap feeder

Scale & honeydew stay heavy: cottony camellia and lecanium scale honeydew, plus crapemyrtle bark scale (males now flying to mate) in the South. Mark calendars — magnolia and Japanese maple scale crawlers emerge in August.

Borer

EAB & wood-boring pests remain active; Oregon's EAB quarantine now spans five Willamette Valley counties. Don't move ash material or firewood, and deep-water stressed trees to limit borer attack.

Disease

Late-summer foliar & scorch: anthracnose, Cercospora, powdery mildew, and honeydew-fed sooty mold are climbing, and bacterial leaf scorch symptoms are appearing on oaks and elms.

Methodology Note

How we report growing degree days

Growing degree days accumulate from January 1 and only climb through the season. Each region's reading is anchored to the latest measured cooperative-extension station data (base 50°F), so figures track real, on-the-ground heat rather than the calendar. Because published station data can lag by a week or two, always confirm against your nearest local station (NEWA, Enviroweather, or your state tool) before timing an application.

Pest on the Chart · This Week

Spotted Lanternfly

Lycorma delicatula

This week's pest on the chart. Nymphs have matured and the first winged adults are emerging across the Mid-Atlantic and Northeast — they'll feed and fly through November. Adults shift onto woody hosts (tree-of-heaven, black walnut, maple, birch, grape), excreting copious honeydew that blackens surfaces with sooty mold and draws yellowjackets and hornets. Established shade trees tolerate the feeding; the real issues are nuisance, honeydew, and hitchhiking spread. Central Maryland — including Howard County — is among the most heavily infested areas.

Stage Now

Adults emerging

Top Hosts

Ailanthus·Walnut

Rx Note

Report + trap

℞ — Scout and report new-county finds to your state ag department. Adults feed mainly on woody trees, so hose saplings to dislodge them and set up tree-of-heaven trap trees for the August adult feeding surge; use neem or pyrethrum only if populations overwhelm. In vineyards, spot-treat the outer ~50 ft with labeled pyrethroids / carbamates / neonicotinoids. Don't panic on established shade trees — focus on honeydew management and preventing spread.

Regional Alert

Oak Wilt Watch

Two new oak wilt confirmations (Bretziella fagacearum) landed this week. Scout oaks for sudden crown wilt and leaf drop, and hold off on any non-emergency oak pruning.

Northeast

Monroe County, NY (Town of Greece) — first confirmed case in the county (NY DEC, July 24). The infected tree is being removed and the stump treated; it follows earlier Ontario and Yates county detections. Report suspect oaks to the DEC Forest Health line, 1-866-640-0652.

South-Central

Arlington, TX (Tarrant County) — a post oak in west Arlington tested positive at the Texas A&M Plant Disease Diagnostic Lab — notable because post oak is a white oak and usually resistant. Reportedly the first local case in ~15 years. Details at TexasOakWilt.org.

℞ Don't wound oaks in the high-risk window (Northeast Mar–Sep; Texas Feb 1–Jun 30) — paint any storm wounds immediately. Confirm by lab, trench to break root grafts around infection centers, destroy infected red oaks (never keep as firewood), and protect high-value oaks with root-flare propiconazole injection.

Regional Rx · 5 Zones

Read your zone like a chart

Each card reports the region's growing-degree-day reading (the vital sign that drives every timing call), what's active now (Diagnose), and how to time treatment (℞). GDD ranges are typical for the week, base 50°F from Jan 1 — always confirm against your nearest station.

NE

Northeast & New England

ME · NH · VT · MA · RI · CT · NY

GDD · Accumulated

~1,300–1,650

0

1,500

3,000+

Conditions: Accumulation climbing from a July 8 UMass average of 1,094 (base 50°F). Drought is deepening — central Massachusetts has slipped into significant drought with scorch and premature leaf drop widespread. UMass's next data drops with their July 24 issue.

Diagnose · Active Now

•

Spotted lanternfly nymphs molting to first adults on tree-of-heaven and grape.

•

Cottony camellia & lecanium scale honeydew on holly, sweetgum; heavy sooty mold.

•

Fall webworm nests enlarging on tupelo and others; box tree moth 2nd-gen larvae on boxwood.

•

Two-spotted & oak spider mites at peak in the dry heat; hibiscus sawfly on hardy hibiscus.

•

Japanese, Oriental & Asiatic garden beetles tapering; anthracnose and leaf spot from the wet-then-dry swings.

℞

Prescribe · Timing & Materials

•

Spotted lanternfly: scout and report; hose saplings; plan tree-of-heaven trap trees for August adults.

•

Fall webworm: prune out nests; Btk / spinosad on young larvae inside opened webs.

•

Scale: hose off; time horticultural oil to crawler emergence (tape-trap the trunk to monitor).

•

Mites & drought: rinse dust, use a selective miticide only if damaging, and deep-water high-value trees; defer pruning to avoid drawing borers.

MA

Mid-Atlantic & DMV

NY · NJ · PA · MD · DE · DC · VA · WV

GDD · Accumulated

~1,900–2,400

0

1,500

3,000+

Conditions: Warm and humid with periodic heavy rain and strong foliar-disease pressure. SLF adults are active in central Maryland — reported in Elkridge, Baltimore, and across Howard and the central counties, the state's most heavily infested region.

Diagnose · Active Now

•

Spotted lanternfly adults emerging and taking flight on woody trees; heavy honeydew, sooty mold, and yellowjackets.

•

Fall webworm nests enlarging; orange-striped oakworm and yellownecked caterpillar beginning.

•

Japanese beetle tapering; crapemyrtle bark scale + aphid sooty mold.

•

Bagworm larvae now large; spider mites and ambrosia beetles on stressed stems.

•

Bacterial leaf scorch symptoms appearing on oaks and elms as summer advances.

℞

Prescribe · Timing & Materials

•

Spotted lanternfly: scout and report new counties; hose saplings; band/trap-tree tree-of-heaven for August adults; neem or pyrethrum only if overwhelming. Adults feed mainly on woody trees.

•

Fall webworm: prune and destroy nests; Btk on young larvae.

•

Bagworm: larvae are large — use chlorantraniliprole (Acelepryn / Mainspring).

•

Crapemyrtle bark scale: systemic imidacloprid / dinotefuran drench with pollinator caution (crape myrtle is a bee pollen source), IGR at crawlers, dormant oil later.

•

Bacterial leaf scorch: no cure — support vigor with water and mulch, remove severely declining limbs, and confirm by lab test.

SE

Southeast

NC · SC · GA · TN · AL · MS · FL · VA

GDD · Accumulated

~2,600–3,600

0

1,500

3,000+

Conditions: Hot and humid; the season's furthest along, with heavy honeydew and sooty-mold load. Late-summer caterpillars are ramping and sap-feeders dominate.

Diagnose · Active Now

•

Crapemyrtle bark scale (males winged and flying to mate; ovisacs and crawlers to follow) + crape myrtle aphid driving sooty mold.

•

Fall webworm large nests on sourwood and pecan; orange-striped oakworm defoliating pin and willow oaks with heavy frass.

•

Yellownecked & azalea caterpillars; lace bugs (azalea, sycamore) stippling.

•

Gloomy, obscure & lecanium scale on maple and oak; southern red spider mite in the heat.

•

Cercospora leaf spot & powdery mildew on crape myrtle; borers on stressed pines and hardwoods.

℞

Prescribe · Timing & Materials

•

Crapemyrtle bark scale: systemic imidacloprid / dinotefuran drench timed to avoid bloom for pollinators, IGR at crawlers, dormant hort oil; conserve lady beetles and lacewings; wash off sooty mold.

•

Late-summer caterpillars: tolerate on large trees; prune webworm nests or Btk on young larvae; handpick oakworm clusters.

•

Lace bugs: hort oil / insecticidal soap to leaf undersides on nymphs.

•

Crape myrtle disease: resistant cultivars, airflow, labeled myclobutanil / propiconazole.

•

Borers: stress reduction and sanitation; do not move infested wood.

MW

Midwest & Great Lakes

OH · MI · IN · IL · WI · MN · IA · MO

GDD · Accumulated

~1,700–2,300

0

1,500

3,000+

Conditions: Development is running ~2 weeks ahead. Japanese beetle edge-feeding is still peaking; hot, dry pockets are driving spider mites near dusty margins. Use MSU Enviroweather / GDDTracker for local timing.

Diagnose · Active Now

•

Japanese beetle at peak — heavy edge-feeding on roses, lindens, and grapes.

•

Emerald ash borer adult flight tapering across the Great Lakes; ash decline and epicormic sprouting.

•

Fall webworm nests appearing; bagworm larvae now large in the southern Midwest.

•

Spider mites flaring in dry pockets; magnolia scale crawler emergence expected in August.

•

Oak wilt risk — warm-season oak wounds invite sap-beetle vectoring.

℞

Prescribe · Timing & Materials

•

Japanese beetle: tolerate light feeding or handpick on specimens; chlorantraniliprole / imidacloprid where thresholds warrant (mind bloom), or carbaryl / permethrin on small trees. Keep lure traps away from valued plants; skip turf irrigation now to discourage egg-laying.

•

EAB: systemic trunk injection (emamectin benzoate) for high-value ash on cycle.

•

Oak wilt: do not prune oaks now; paint any unavoidable wounds immediately.

•

Webworm / bagworm: prune webworm nests; use chlorantraniliprole for large bagworm.

•

Magnolia scale: mark late August for crawler-timed hort oil + IGR.

W

West & Pacific

CA · OR · WA · NV · AZ · CO · UT · ID · MT

GDD · Accumulated

Highly variable

Coast / high elev.

—

Inland / low desert

Conditions: Wide range by elevation and coast vs. inland; irrigation-driven stress is the key variable and fire season is in full swing across the interior West.

Diagnose · Active Now

•

Wood-boring beetles on stressed trees — invasive shothole borers in SoCal urban forests, goldspotted oak borer on SoCal oaks, Mediterranean oak borer.

•

Emerald ash borer in Oregon — the permanent quarantine now covers five counties (Washington, Yamhill, Marion, Clackamas, Multnomah).

•

Spider mites at peak in heat and road dust; aphids with honeydew and sooty mold.

•

Bacterial blast / canker on stone fruit and citrus; yellowjackets building.

℞

Prescribe · Timing & Materials

•

Borers: deep-water summer-rainfall-adapted trees, avoid fresh wounds, and do not move ash material or firewood; in EAB zones, inventory ash and consider systemic protection, then report.

•

Spider mites: rinse dust, use hort oil or a selective miticide only if damaging; protect predators.

•

Aphids: strong water spray, conserve natural enemies, tolerate on established plants.

•

Stone-fruit canker/blight: prune out in dry weather, cutting several inches into healthy wood.

•

Fire: maintain defensible space and thin fuel ladders around trees and structures.

Field notes — read before you spray

Catch caterpillars early. Fall webworm and the late-summer defoliators are far easier to prune out now than in three weeks; tolerate light feeding on large, healthy trees.

Mites are peaking. Scout dusty, drought-stressed canopies, shake branches over white paper to confirm, hose before you spray, and reserve miticides for real damage to protect predators.

Don't move wood. With EAB and other borers active — and Oregon's five-county quarantine in effect — keep ash material and firewood local.

Sources · Cooperative Extension & USDA

Compiled from public reporting by land-grant cooperative extension services and USDA partners, including UMass Extension Landscape Message; University of Maryland Extension IPMnet & Maryland Dept. of Agriculture; Rutgers Plant & Pest Advisory; NC State Extension, Clemson HGIC & UGA; Michigan State University Extension & Enviroweather; Iowa State ICM; UC Statewide IPM Program; Oregon Dept. of Agriculture / ODF EAB program; and USDA NIFA / USDA Forest Service cooperative forest-health programs. Regional summaries are paraphrased; consult the original bulletins and your local extension office for specifics.

Manage fall webworm, mites, and SLF with region-specific pest control advice.

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