Quick Reference

Scientific Name	Hyphantria cunea
Classification	Insecta / Lepidoptera / Erebidae
Size	Larvae: 1 to 1.5 inches long (about the size of a AAA battery); Adults: 1 to 1.4 inch wingspan
Color	Larvae: pale yellow to greenish with black spots and long white hairs; Adults: white moths, sometimes with small dark spots on wings
Lifespan	One generation completes in 6 to 8 weeks; adults live approximately one week
Diet	Leaves of over 600 deciduous tree and shrub species, with strong preference for pecan, walnut, persimmon, sweetgum, hickory, and elm
Active Season	Two generations per year in Oklahoma: June through July (first generation) and August through October (second generation, larger and more visible)
Threat Level	Low to moderate. Primarily cosmetic damage to established trees. Young or stressed trees may need protection.
Common in OKC Metro	Yes. Extremely common across the metro, especially on pecan, walnut, and sweetgum trees. Late summer web explosions are a yearly event.

Every late summer and early fall, Oklahoma City homeowners look up at their pecan trees, sweetgums, and walnuts and see large, silky white webs engulfing the ends of branches. These webs, sometimes stretching two to three feet long and covering entire branch tips, belong to the fall webworm (Hyphantria cunea), one of the most common and most visible landscape pests in the state. The fall webworm is a native North American caterpillar that feeds communally inside protective silk tents, and it has been reported on more than 600 species of deciduous trees and shrubs. In central Oklahoma, pecan trees are the primary target, and because pecans are one of the most abundant yard trees across the OKC metro, fall webworm webs are nearly impossible to avoid. Despite their alarming appearance, fall webworms rarely cause lasting damage to healthy, established trees. The defoliation is cosmetic in most cases, and trees recover fully the following spring. However, repeated heavy infestations on young trees or drought-stressed trees can weaken them over time. Alpha Pest Solutions provides professional fall webworm and caterpillar management across the Oklahoma City metro. If webs are spreading through your trees and you want them controlled before they cover every branch, call or text (405) 977-0678 for a free inspection.

Identifying Fall Webworms in Oklahoma

Fall webworms are easy to identify once you understand what you are looking at, but they are routinely confused with two other common Oklahoma pests: Eastern tent caterpillars and bagworms. Correct identification matters because the timing, biology, and treatment approach differ for each.

Web appearance and location. The most obvious sign of fall webworms is the silk web itself. Fall webworm webs are loose, messy, whitish silk tents that enclose the tips of tree branches. The web expands outward as the larvae grow, engulfing more and more leaves at the branch ends. Webs can grow from a few inches to three feet or more in length on heavily infested branches. The larvae feed inside the web, consuming the enclosed leaves and expanding the tent to reach fresh foliage. Frass (caterpillar droppings), shed skins, and dead leaf fragments accumulate inside the web, giving older webs a dirty, brownish appearance.

Larval appearance. Fall webworm larvae are about 1 to 1.5 inches long when mature, roughly the length of a AAA battery. They are pale yellow to greenish-yellow with rows of black spots or tubercles running along the body. Long, silky white hairs emerge from these tubercles, giving the caterpillar a fuzzy appearance. There are two color forms in North America: a pale or yellow-headed form and a darker, black-headed form. Both forms occur in Oklahoma, but the pale form is more common in the southern Plains states. The caterpillars are gregarious and feed in groups inside the web.

Adult moth. The adult fall webworm moth is a small to medium white moth with a wingspan of about 1 to 1.4 inches. Some individuals have small black or brown spots scattered on the forewings, while others are pure white. Adults are nocturnal and are attracted to lights. They do not feed as adults and live only about one week, during which they mate and lay eggs.

Egg masses. Female moths lay eggs in flat clusters of 200 to 500 on the undersides of host tree leaves. The egg mass is covered with white hairs from the female’s abdomen, making it look like a small patch of white fuzz on the leaf underside. Eggs are pale green to yellow when fresh and darken before hatching.

Fall Webworm vs. Eastern Tent Caterpillar

This is the single most common misidentification in Oklahoma. Homeowners see webs in their trees and call them “tent caterpillars” or “tent worms,” but in late summer and fall, the pest is almost always the fall webworm, not the Eastern tent caterpillar. The two species are completely different insects with different life cycles, different web locations, and different seasonal timing.

Web location. Eastern tent caterpillars build their webs in the forks and crotches of branches, where two or more branches meet. Fall webworms build their webs at the tips of branches, enclosing the outermost leaves. This single difference is the fastest way to tell them apart.

Seasonal timing. Eastern tent caterpillars are active in spring (March through May in Oklahoma). Fall webworms are active in summer and fall (June through October in Oklahoma). If you see webs in your trees in August or September, they are fall webworms, not tent caterpillars.

Host trees. Eastern tent caterpillars prefer cherry, crabapple, and apple trees. Fall webworms attack a much broader range of trees, with pecan, walnut, persimmon, and sweetgum being the most common targets in Oklahoma.

Larval behavior. Eastern tent caterpillars leave their web during the day to feed on nearby branches, then return to the web at night. Fall webworm larvae stay inside their web and feed on the enclosed leaves. The web expands to reach new foliage rather than the larvae leaving the web to find it.

Treatment timing. Treating for Eastern tent caterpillars happens in early spring. Treating for fall webworms happens in summer and early fall. Applying the wrong treatment at the wrong time wastes money and product.

Fall Webworm vs. Bagworm

Bagworms (Thyridopteryx ephemeraeformis) are another extremely common Oklahoma tree pest, and some homeowners confuse them with webworms. The two are easy to tell apart once you know what to look for.

Bagworms create individual, spindle-shaped bags made of silk and bits of foliage. Each bag contains a single caterpillar. The bags hang from branches like small ornaments, typically 1 to 2 inches long. Bagworms prefer evergreen trees, especially Eastern red cedar and arborvitae, though they attack over 100 species.

Fall webworms create large communal silk tents that enclose branch tips. Dozens to hundreds of caterpillars live together inside a single web. They prefer deciduous trees, especially pecan, walnut, and sweetgum.

Key differences at a glance:

• Bagworms: individual hanging bags, one larva per bag, prefer evergreens
• Fall webworms: large communal webs at branch tips, many larvae per web, prefer deciduous trees
• Bagworms: active May through August in Oklahoma
• Fall webworms: active June through October in Oklahoma, with peak webbing in August and September

For comprehensive bagworm information, see our bagworm identification and control page. Alpha Pest Solutions also offers professional bagworm and webworm treatment across the OKC metro.

Types Found in Oklahoma

The fall webworm (Hyphantria cunea) is the only webworm species in the family that creates the large branch-tip webs Oklahoma homeowners recognize. However, the species exhibits significant variation within its population.

Two color forms. Fall webworms come in two recognized color forms, and both occur in Oklahoma:

• Pale or red-headed form. Larvae have reddish-orange head capsules and pale yellowish-green bodies with lighter-colored hairs. This form tends to produce smaller, less dense webs and is more common in the southern portion of the fall webworm’s range, including Oklahoma.
• Black-headed form. Larvae have dark black head capsules and darker bodies with more pronounced black spots. Their webs tend to be denser and more tightly woven. This form is more common in northern states but does occur in Oklahoma.

Why it matters. The two forms can interbreed and are not separate species. Both respond to the same treatment methods. However, the black-headed form tends to produce denser webs that are more difficult for predators and parasitoids to penetrate, which can lead to larger colonies persisting longer on a tree.

No other web-spinning caterpillar in Oklahoma produces the characteristic branch-tip silk tents of the fall webworm. If you see communal webs at branch ends on deciduous trees in late summer, it is Hyphantria cunea.

Diet, Behavior, and Habitat

Diet

The fall webworm is one of the most generalist feeders of any caterpillar in North America, with confirmed host records on over 600 species of deciduous trees and shrubs. According to OSU Extension, the fall webworm will feed on nearly any deciduous tree, but it has clear preferences in Oklahoma landscapes.

Most commonly attacked trees in OKC metro:

• Pecan is the number one host tree in central Oklahoma. Pecans are planted across virtually every neighborhood in the metro, from the large established trees in Nichols Hills and The Village to the younger plantings in south OKC and Moore. Fall webworms in pecan trees are the single most common tree pest complaint in the OKC metro from August through October.
• Walnut (both black walnut and English walnut) is heavily attacked.
• Persimmon is a common native tree in Oklahoma landscapes and a major webworm host.
• Sweetgum trees in neighborhoods across Edmond, Norman, and Midwest City are frequently covered in webs.
• Hickory trees in more rural and semi-rural areas around Choctaw, east Edmond, and south OKC are common hosts.
• Elm trees, including the American elm, are attacked, though less heavily than pecan.
• Mulberry, cottonwood, redbud, and crabapple are all occasional hosts.

The larvae eat the leaves enclosed within the web. They consume the soft tissue between the veins first, creating a skeletonized appearance, then eat the entire leaf as they grow. On heavily infested branches, every leaf inside the web is consumed, and the web expands to engulf new foliage.

Behavior

Communal feeding. Fall webworm larvae are social caterpillars. The female moth lays her eggs in a single mass, and when the larvae hatch, they immediately begin spinning silk together. The entire group feeds, grows, and molts inside the expanding web. This communal behavior provides protection from many predators and from drying wind and rain.

Web expansion. As the colony grows and consumes the enclosed leaves, the larvae extend the web outward to cover new branch tips. A single web can eventually cover two to three feet of branch length. On heavily infested trees, multiple webs merge, and entire branches appear to be cocooned in silk.

Frass accumulation. Caterpillar droppings, shed larval skins, and leaf debris accumulate inside the web, making older webs look dirty and ragged. The frass is visible as small dark pellets scattered on the web surface and inside it.

Late-stage dispersal. When mature (fifth or sixth instar), the larvae leave the web and crawl down the tree trunk or drop on silk threads to pupate in the soil or leaf litter. Homeowners sometimes find large caterpillars crawling on siding, porches, or foundations during this dispersal phase in September and October.

Habitat

Fall webworms are found wherever deciduous trees grow, which means they are present across the entire Oklahoma City metro. They are most abundant in areas with:

• Dense stands of preferred host trees, especially pecan
• Irrigated landscapes that keep trees leafy through the hot summer
• Neighborhoods with large, mature trees that provide abundant foliage
• Areas near creeks, rivers, and bottomland where walnut, pecan, and sweetgum thrive naturally

Life Cycle and Reproduction

The fall webworm has a complete metamorphosis life cycle with four stages: egg, larva, pupa, and adult. In Oklahoma, there are typically two generations per year, and the second generation (August through October) is the one that produces the large, conspicuous webs homeowners notice.

Overwintering Pupae

Fall webworms overwinter as pupae in the soil, leaf litter, or under loose bark. The pupae are dark brown, about 1/2 inch long, and enclosed in a thin silk cocoon mixed with soil particles and debris. They can survive Oklahoma’s winter temperatures without difficulty.

Adult Emergence and Egg Laying (May through July)

Adults emerge from overwintering pupae in late May through June in central Oklahoma. The white moths are nocturnal and fly to host trees, where they mate. Females lay flat egg masses of 200 to 500 eggs on the undersides of leaves on preferred host trees. The eggs are covered with white hairs from the female’s body. Eggs hatch in about 7 to 10 days.

First Generation Larvae (June through July)

First-generation larvae hatch and begin spinning small webs at branch tips. This generation is typically smaller, produces less conspicuous webs, and causes less noticeable damage. Many homeowners never notice the first generation because the webs are smaller and trees are still leafing out heavily in June. First-generation larvae complete development in 4 to 6 weeks, pupate, and the resulting adults emerge to begin the second generation.

Second Generation Larvae (August through October)

The second generation is the one Oklahoma homeowners see. Webs from the second generation are larger, more numerous, and more conspicuous because:

• There are more moths laying eggs (population has multiplied)
• Trees are fully leafed out, providing maximum food
• Late summer heat accelerates larval development
• Webs persist longer because there is no new foliage growth to outpace the feeding

This generation produces the dramatic web explosions that cover pecan trees across the OKC metro from mid-August through October. According to OSU Extension, the second generation consistently causes more visible damage than the first.

Pupation and Cycle Completion

Mature larvae leave the webs in September and October, crawl down the tree or drop to the ground, and pupate in the soil or leaf litter. These pupae will overwinter and emerge as adults the following May or June, completing the annual cycle.

Reproduction numbers. A single female moth lays 200 to 500 eggs. With two generations per year and favorable conditions, one overwintering pupa can theoretically produce hundreds of descendants by fall. This exponential growth explains why webworm populations seem to explode in late summer.

What Attracts Fall Webworms to Oklahoma Homes

Fall webworms are attracted to properties that provide their two essential needs: suitable host trees and favorable environmental conditions.

Pecan trees. This is the single biggest factor in Oklahoma. If you have pecan trees in your yard, you will almost certainly have fall webworms at some point. Pecans are among the most common residential trees in the OKC metro, planted in yards across every neighborhood from Nichols Hills to Moore. Pecan trees provide abundant foliage, and fall webworms preferentially select them over many other species.

Other preferred host trees. Walnut, sweetgum, persimmon, hickory, and elm trees all attract fall webworms. Properties with multiple host species may see webworms move from tree to tree throughout the season.

Outdoor lighting. Adult fall webworm moths are attracted to artificial light. Properties with bright porch lights, landscape lighting, and security lights may attract more egg-laying females to nearby trees.

Irrigated landscapes. Trees that receive regular watering maintain lush, green foliage through the hot Oklahoma summer, which provides better food quality for developing larvae. Irrigated trees may support larger webworm colonies than drought-stressed trees with reduced foliage.

Proximity to creek bottoms and natural areas. Properties near creeks, rivers, and undeveloped areas with native pecan, walnut, and persimmon stands are adjacent to natural fall webworm populations that can spread into residential landscapes.

Oklahoma’s clay soils. The red clay soils common across the OKC metro retain moisture well, which supports healthy tree growth and provides good overwintering habitat for pupae in the soil.

Where Found in OKC Metro

Fall webworms are found across the entire Oklahoma City metropolitan area. There is no neighborhood, suburb, or community in the metro that is free of them. However, certain areas experience heavier infestations due to tree composition and environmental factors.

Nichols Hills and The Village. These established neighborhoods have some of the largest, most mature pecan and walnut trees in the metro. The dense tree canopy supports heavy fall webworm populations every year. Large pecan trees in these neighborhoods can have dozens of visible webs by September.

Edmond. Older neighborhoods in central and south Edmond with mature pecan, sweetgum, and elm trees see consistent webworm pressure. Newer developments on the north side of Edmond have younger trees with lower but growing webworm populations.

Norman. The established neighborhoods around the University of Oklahoma campus and through central Norman have abundant pecan and walnut trees. Fall webworm webs are a standard late-summer feature across Norman.

Midwest City and Del City. Mature residential neighborhoods with large shade trees see annual webworm infestations. The creek drainages through these areas support native host trees that serve as reservoirs for webworm populations.

South OKC, Moore, and Mustang. Residential areas with established pecan trees experience heavy webworm pressure. Properties near the Canadian River corridor and its tributaries are adjacent to native pecan, cottonwood, and walnut stands with natural webworm populations.

Yukon and Bethany. Suburban neighborhoods with mature landscape trees see typical fall webworm activity. Properties with pecan trees planted 20 or more years ago tend to have the heaviest infestations.

Choctaw. The semi-rural character of much of Choctaw means properties are often adjacent to or contain native woodland with pecan, hickory, and persimmon, all prime webworm hosts.

Where Found on Property

In trees. Fall webworm webs are found in the canopy of deciduous trees, always at the branch tips. Webs start small (a few inches) and expand outward to cover more foliage. On large pecan trees, webs can form at various heights from low-hanging branches at 8 to 10 feet up to the top of the canopy at 50 feet or more.

On tree trunks and bark. In September and October, mature larvae crawl down tree trunks to reach the soil for pupation. Homeowners may see caterpillars moving down the bark in large numbers during this dispersal phase.

On exterior walls and siding. Dispersing larvae sometimes crawl onto homes, garages, and fences adjacent to infested trees. They are looking for a place to pupate, not trying to enter the structure.

On porches, decks, and patios. Caterpillars that drop from overhead tree branches on silk threads may land on outdoor living spaces below. Frass (droppings) and silk strands also fall from webs onto surfaces beneath infested branches.

In leaf litter and mulch beds. Pupae overwinter in leaf litter, soil, and mulch at the base of host trees. This is where next year’s population is hiding.

Around outdoor lights. Adult moths are attracted to porch lights, garage lights, and landscape lighting, and may be found resting on walls and windows near these light sources in early summer.

Signs of Infestation

Silk webs at branch tips. The most obvious sign. White to grayish silk webs enclosing the ends of tree branches, starting small and growing to two or three feet in length. Multiple webs on a single tree indicate a heavier infestation. This is the sign that prompts most homeowner calls.

Skeletonized leaves. Inside and around the web, leaves are eaten down to the veins, leaving a lacy or skeleton-like appearance. This progresses to complete leaf consumption as the colony grows.

Frass inside and below webs. Small dark droppings (about the size of a poppy seed) accumulate inside the web and fall onto surfaces below. If you see tiny dark pellets on a patio table or car parked under a tree, look up for webs.

Shed larval skins. As caterpillars molt through their growth stages, the cast skins accumulate inside the web, adding to the dirty appearance of older webs.

Caterpillars on tree trunk. In late summer and early fall, mature larvae leaving the web crawl down the trunk in noticeable numbers. Finding fuzzy, pale caterpillars on your tree trunk in September indicates an active webworm colony in the canopy above.

Caterpillars on structures. Dispersing larvae on house walls, fences, and foundations near infested trees are a late-season sign.

Defoliated branch tips. After the larvae finish feeding and leave the web, the branch tips are completely bare of leaves while the rest of the tree remains green. This partial defoliation pattern is distinctive.

White moths around lights. In May through July, white moths at porch lights and windows may be fall webworm adults. While many white moths exist, a large number appearing when host trees are nearby can indicate a building population.

How to Tell If the Infestation Is Active

Fall webworms leave their webs behind when they finish feeding and disperse to pupate. An old, empty web can hang in a tree for weeks or months. Here is how to determine if a web is active or abandoned.

Look for movement inside the web. Active webs contain caterpillars that are visibly moving and feeding. Use binoculars if the web is high in the tree. If you can see caterpillars inside, the infestation is active.

Check web color and condition. Fresh, active webs are white to light gray and relatively clean. Old, abandoned webs are brown, tattered, and full of dried frass and debris. Rain and wind break down abandoned webs over time.

Look for fresh frass. Active colonies produce fresh droppings that are dark and moist. If you see fresh, dark pellets falling from a web or accumulating on surfaces below, the colony is still feeding.

Check for green leaves inside the web. If the web still encloses green or partially eaten leaves, the larvae are likely still present and feeding. If all enclosed leaves are completely consumed and brown, the colony may have already dispersed.

Check the season. In Oklahoma, active webworm feeding occurs from June through October. Webs visible in November through May are abandoned remnants from the previous season.

Tap the branch. If you can reach the branch, tap it or shake it gently. Active larvae will react by moving or dropping on silk threads. An empty web will not produce any movement.

Fall Webworm Season in Oklahoma

Fall webworms have a predictable seasonal pattern in central Oklahoma, driven by temperature and day length.

May through early June. Overwintering pupae transform into adult moths and begin emerging from the soil. Adults fly at night and are attracted to lights. Mating and egg laying begin on host trees.

June through July. First-generation larvae hatch, spin small webs at branch tips, and feed. These webs are relatively small and often go unnoticed by homeowners. First-generation webs are most visible on lower branches of pecan, walnut, and persimmon trees.

Late July through early August. First-generation larvae complete development, pupate, and adults from the second generation emerge. Egg laying for the second generation begins.

August through September. This is peak fall webworm season in Oklahoma. Second-generation larvae produce large, conspicuous webs that are impossible to miss. Webs expand rapidly as colonies grow. This is when most homeowners notice the problem and call for help. Trees across the OKC metro can appear heavily infested, especially pecans.

October. Mature second-generation larvae leave their webs and disperse to pupate. Caterpillars are found crawling on tree trunks, fences, and structures. Web activity declines as the season cools. Late webs may persist on trees.

November through April. No active webworm activity. Pupae overwinter in the soil and leaf litter. Old webs may remain visible in trees throughout winter until wind and rain break them down.

Health Risks

Fall webworms pose no health risks to humans or pets. They do not bite, sting, or transmit diseases. The caterpillars are not venomous, and their hairs are not urticating (they do not cause skin irritation like some other caterpillar species).

No structural risk. Fall webworms do not enter homes, infest food, or damage structures. They are strictly outdoor, tree-feeding insects.

No risk to pets. Dogs and cats that encounter or eat fall webworm caterpillars are not at risk of poisoning. The caterpillars contain no toxins.

The only concern is tree health, which is addressed in the property damage section below.

Property and Structural Damage

Fall webworm damage is primarily cosmetic, but homeowners should understand what the actual risks are and when professional intervention is warranted.

Cosmetic defoliation. The most common damage is partial defoliation of branch tips where webs form. On mature, healthy pecan and walnut trees, this defoliation has minimal impact on overall tree health. The tree has already produced and stored most of its energy for the year by the time fall webworms cause their heaviest defoliation in August and September. According to OSU Extension, healthy established trees almost always recover fully from fall webworm defoliation without long-term harm.

Aesthetic impact. Large webs are unsightly, and heavy infestations can make a tree look severely damaged even when the actual threat to the tree is low. For homeowners who take pride in their landscape, the visual impact alone is often reason enough to treat.

Young or newly planted trees. Trees planted within the last 3 to 5 years that have not yet established a robust root system and canopy are more vulnerable to defoliation stress. Heavy webworm feeding on young trees can reduce growth rates and weaken the tree’s ability to establish.

Drought-stressed trees. Trees already stressed by Oklahoma’s hot, dry summers may be less able to recover from additional defoliation. The combination of drought stress and webworm feeding can push a struggling tree toward decline.

Repeated heavy infestations. A single season of heavy webworm activity is unlikely to cause lasting damage. However, multiple consecutive years of severe defoliation can reduce a tree’s energy reserves and make it more susceptible to other pests and diseases.

Pecan crop impact. For Oklahoma homeowners who harvest pecans, fall webworm defoliation in August and September can reduce nut size and fill. This is the period when pecans are filling out, and loss of leaf surface area reduces the tree’s ability to photosynthesize and nourish the developing nuts.

No structural damage to homes. Fall webworms do not damage buildings, roofing, siding, or foundations. They are entirely a landscape pest.

Prevention

Preventing fall webworms entirely is not realistic for Oklahoma homeowners with pecan trees or other preferred host species. However, these steps can reduce the severity of infestations and protect vulnerable trees.

• Monitor trees beginning in June. Start checking branch tips on pecan, walnut, sweetgum, and persimmon trees for small, newly formed webs starting in early June. First-generation webs are small and easy to miss but catching them early makes control simpler.
• Remove small webs manually. When webs are first forming and still small (under 6 inches), they can be pruned out with a pole pruner or long-handled lopper. Cut the branch 6 to 12 inches behind the web to remove the entire colony. Bag and dispose of the pruned material.
• Open webs to expose larvae. If you cannot prune the branch, use a long stick, broom handle, or pole to tear open the web. This exposes the larvae to predators, parasitoid wasps, and weather. Birds, paper wasps, and other natural enemies are highly effective at controlling exposed webworm larvae.
• Reduce outdoor lighting near host trees. Because adult moths are attracted to light, reducing or redirecting exterior lighting away from host trees can reduce the number of egg-laying females attracted to your specific trees.
• Clean up leaf litter in fall. Fall webworm pupae overwinter in leaf litter and soil beneath host trees. Raking and removing or composting leaf litter in November and December removes a portion of the overwintering pupae and can reduce the following year’s first-generation population.
• Maintain tree health. Healthy trees tolerate webworm defoliation far better than stressed trees. Water trees deeply during drought, avoid soil compaction over root zones, and address any other health issues. A healthy pecan tree in Oklahoma can sustain significant webworm activity without lasting harm.
• Encourage natural predators. Paper wasps, yellowjackets, birds (especially cuckoos, vireos, and warblers), and parasitoid wasps all feed on fall webworm larvae. Maintaining a diverse landscape with native plantings supports these beneficial predator populations.
• Do not burn webs. This is a persistent piece of bad advice. Using a propane torch or fire to burn webs in trees can damage the bark, kill branches, and even start fires. Never attempt to burn webworm webs.

Treatment Process

When fall webworm populations are heavy enough to warrant treatment, Alpha Pest Solutions follows a systematic approach tailored to the severity of the infestation and the value of the trees involved.

Step 1: Inspection and Assessment

A technician inspects all trees on the property, identifies the species and host trees affected, assesses the severity of the infestation, and determines whether the trees are healthy enough to tolerate the defoliation or whether treatment is necessary. Young trees, high-value pecans, and stressed trees are prioritized for treatment.

Step 2: Physical Removal Where Accessible

For webs on lower branches that can be reached safely, physical removal by pruning is the most immediate and effective control. The infested branch tip is pruned 6 to 12 inches behind the web and disposed of. This eliminates the colony completely with zero chemical use.

Step 3: Biological Treatment (Bt Application)

For trees where physical removal is impractical (webs too high or too numerous), we apply Bacillus thuringiensis var. kurstaki (Btk), a naturally occurring soil bacterium that is specifically lethal to caterpillars. Bt is applied as a spray to the foliage around and within the webs. When caterpillars ingest Bt-treated foliage, they stop feeding and die within 2 to 3 days. Bt is most effective on young larvae (first through third instar). It has no effect on mammals, birds, fish, or beneficial insects other than caterpillars.

Step 4: Insecticidal Treatment for Heavy Infestations

For severe infestations where webs are extensive, Bt alone may not penetrate the dense silk effectively, or larvae may be too mature for Bt to be fully effective. In these cases, we use targeted insecticide applications that penetrate the web and contact the larvae directly. Products are selected for effectiveness against caterpillars while minimizing impact on beneficial insects.

Step 5: Web Opening for Natural Predator Access

After treatment, webs are physically opened where accessible to allow birds, paper wasps, and parasitoid wasps to reach the dying or weakened larvae inside. This natural cleanup accelerates colony collapse and reduces the number of larvae that survive to pupate.

Step 6: Follow-Up Monitoring

Because fall webworms can have two generations per year in Oklahoma, a second wave of webbing may appear in August or September after a June-July treatment. We monitor treated properties through October and retreat if second-generation populations warrant intervention.

Treatment Timeline and Expectations

Day 1: Inspection and first treatment. The technician assesses all trees, performs physical removal on accessible webs, and applies Bt or targeted insecticide to remaining webs.

Days 2 through 5: Feeding cessation. Larvae that have ingested Bt stop feeding within 24 hours and die within 2 to 5 days. Webs stop expanding. Contact insecticides work faster, with larval mortality typically within 24 to 48 hours.

Week 1 through 2: Web deterioration. Without active larvae maintaining them, webs begin to break down. Rain and wind collapse treated webs. Dead larvae, frass, and silk debris fall from the tree.

Week 2 through 4: Cosmetic recovery. Dead webs may remain visible in the tree for several weeks before weather breaks them apart. The underlying defoliation (bare branch tips) will remain visible until new growth appears the following spring.

Second generation watch (August through October). If the first generation was treated in June or July, the property is monitored for second-generation webs beginning in August. Second-generation treatment follows the same process if needed.

What to expect after treatment. The webs will not disappear immediately. Old silk persists in trees until weathered away. Branch tips that were defoliated will remain bare for the rest of the season. Healthy trees will produce normal foliage the following spring with no lasting damage. Some caterpillars that had already left the web to pupate before treatment will not be affected, so a small population may persist into the next year.

Frequently Asked Questions

Are fall webworms harmful to my pecan tree?

For healthy, mature pecan trees, fall webworm damage is almost always cosmetic. The defoliation occurs late enough in the growing season that the tree has already stored most of its energy. According to OSU Extension, established pecans recover fully in the vast majority of cases. The exception is trees that are already stressed by drought, disease, or root damage, or young trees that have not yet fully established. For these trees, heavy webworm defoliation can add significant stress. If you are harvesting pecans for the nuts, webworm defoliation during the August and September fill period can reduce nut size and quality.

Will fall webworms kill my tree?

It is extremely rare for fall webworms to kill a tree. Even heavy defoliation of branch tips on a mature tree represents only a fraction of the tree’s total leaf area. Trees have evolved to tolerate partial defoliation from insects, storms, and other stresses. The risk increases only with repeated heavy infestations over multiple consecutive years on trees that are already weakened. If your tree is young (planted within the last 3 to 5 years) or visibly stressed, proactive treatment is a reasonable precaution.

What is the difference between fall webworms and tent caterpillars?

Fall webworms make webs at branch tips in late summer and fall (August through October in Oklahoma). Eastern tent caterpillars make webs in branch crotches in spring (March through May). They are completely different species. If you see webs in your trees during August or September, you are looking at fall webworms, not tent caterpillars. Fall webworms feed inside their webs, while tent caterpillars leave their webs to feed on nearby branches.

Should I spray my trees for fall webworms?

It depends on the severity and the trees involved. Healthy mature pecan and shade trees usually tolerate fall webworm damage without needing treatment. Treatment is most warranted for young trees, trees you are harvesting pecans from, and trees where the aesthetic impact is unacceptable. Bt (Bacillus thuringiensis) is the most targeted and environmentally responsible spray option and works best when applied to young larvae early in the web formation. Call Alpha Pest Solutions at (405) 977-0678 for a professional assessment.

Can I just pull the webs out of my tree?

Yes, and this is one of the most effective control methods for accessible webs. Use a pole pruner or long-handled tool to either prune out the webbed branch tip or physically tear open the web. Opening the web exposes the larvae to birds, wasps, and weather, which typically eliminates the colony without any chemical treatment. Do this as soon as you notice webs forming for the best results.

Is it safe to burn fall webworm webs out of trees?

No. Never use fire to remove webs from trees. Torching webs with a propane torch or lighter damages bark, kills branches, and creates a serious fire hazard, especially during Oklahoma’s dry late-summer conditions. The heat damage to the tree from burning is almost always worse than the webworm damage itself. Pruning and Bt application are safer and more effective.

When do fall webworms appear in Oklahoma?

The first generation of fall webworms appears in June through July, but these webs are small and often go unnoticed. The second generation, which creates the large, conspicuous webs that homeowners notice, appears from mid-August through October. This is the peak fall webworm season in the OKC metro.

Do fall webworms come back every year?

Yes. Fall webworms are a native insect with a stable population across Oklahoma. Every year, overwintering pupae in the soil emerge as adults, lay eggs, and produce a new generation of web-spinning larvae. Population levels fluctuate from year to year based on weather conditions, natural predator populations, and other factors, but some level of fall webworm activity occurs every summer and fall in the OKC metro.

What trees do fall webworms prefer in Oklahoma?

In the OKC metro, pecan is the number one target by a wide margin. Walnut, persimmon, sweetgum, hickory, and elm are also heavily attacked. Fall webworms have been recorded on over 600 species of deciduous trees and shrubs, so virtually any deciduous tree in your yard could be a host. Evergreen trees (pines, cedars, spruces) are not attacked by fall webworms.

Do fall webworms bite or sting?

No. Fall webworm caterpillars do not bite, sting, or cause skin irritation. Their long white hairs are not urticating (they do not inject venom or cause rashes). The caterpillars, adult moths, and silk webs are all completely harmless to humans and pets. Fall webworms are purely a landscape pest with no health risk.

Can fall webworms infest my house?

No. Fall webworms are strictly outdoor, tree-feeding insects. They do not enter homes, infest food, or damage structures. The only time homeowners find caterpillars on their house is during the late-season dispersal phase when mature larvae crawl down from trees and may wander onto nearby structures while looking for a place to pupate in the soil. They will not survive indoors and are not seeking to enter your home.

What eats fall webworms?

Fall webworms have many natural enemies in Oklahoma. Paper wasps and yellowjackets tear open webs and feed on the larvae. Birds, especially yellow-billed cuckoos (sometimes called “rain crows”), are voracious webworm predators. Parasitoid wasps and tachinid flies lay eggs in or on webworm larvae, and their offspring consume the caterpillar from within. When webs are opened or disturbed, these natural enemies quickly find and consume the exposed larvae.

How do I keep fall webworms off my trees next year?

Complete prevention is not realistic if you have preferred host trees like pecan or walnut. However, you can reduce populations by raking and removing leaf litter beneath host trees in November (to remove overwintering pupae), reducing outdoor lighting near host trees (to attract fewer egg-laying moths), and monitoring trees starting in June to catch and remove first-generation webs when they are small. Encouraging natural predators by maintaining a diverse landscape also helps keep populations in check.

Are fall webworms the same as bagworms?

No. Fall webworms and bagworms are completely different insects. Fall webworms create large communal silk webs at branch tips on deciduous trees, with many caterpillars living inside one web. Bagworms create individual, spindle-shaped bags made of silk and plant material, with one caterpillar per bag, and they primarily attack evergreen trees like Eastern red cedar and arborvitae. Both are common in Oklahoma, but they require different identification and different treatment approaches. See our bagworm page for complete bagworm identification and control information.

How fast do fall webworm webs grow?

A new web can go from barely visible to covering 12 inches of branch tip within a week under good conditions. Over the course of a 4 to 6 week larval feeding period, a single web can expand to enclose 2 to 3 feet of branch length. On heavily infested trees, multiple webs can merge and cover entire sections of the canopy. The growth rate depends on colony size, temperature, and food quality.

Does Oklahoma have more fall webworms than other states?

Oklahoma’s climate, abundant pecan trees, and long warm season make it one of the states where fall webworms are most visible and most complained about. The combination of two full generations per year, millions of pecan trees across the state, and warm late-summer conditions that support rapid larval development produces heavy webworm years that are among the most intense in the central United States. OSU Extension receives more calls about fall webworms than almost any other landscape insect pest.

Is Bt safe to use around my vegetable garden and pets?

Yes. Bacillus thuringiensis var. kurstaki (Btk) is one of the safest biological pesticides available. It specifically targets caterpillars (larvae of moths and butterflies) and has no toxicity to mammals, birds, fish, bees, or other non-caterpillar insects. It is approved for use in organic agriculture by the USDA. Bt breaks down quickly in sunlight and does not persist in the environment. It is safe to use near vegetable gardens, around pets, and in areas where children play.

When is the best time to treat fall webworms in Oklahoma?

The best time to treat is when webs are small and larvae are young. For the first generation, that means June through early July. For the second generation (the one most homeowners notice), that means mid-August through early September. Bt is most effective on young larvae in the first through third instar. Once larvae are large and mature (late September into October), they are preparing to leave the web and pupate, so treatment at that point has limited benefit.

Related Services and Pests

Alpha Pest Solutions provides comprehensive tree pest and caterpillar control across the Oklahoma City metro. If you are dealing with fall webworms, you may also want to learn about these related pests and services:

• Bagworm and Webworm Treatment – Professional treatment for both bagworms and webworms on your property
• Bagworm Identification and Control – Complete guide to identifying and controlling bagworms on evergreen and deciduous trees
• Armyworm Control – Another common Oklahoma caterpillar pest that damages lawns and landscapes
• General Pest Control – Comprehensive pest management for your home and property
• Pest Library – Browse our complete library of Oklahoma pest identification and control guides

Get Rid of Fall Webworms in Your Oklahoma City Trees

Fall webworms are a fact of life for Oklahoma homeowners with pecan trees, walnuts, sweetgums, and other deciduous shade trees. While the webs look alarming, most healthy trees handle the defoliation without lasting harm. But when webs are spreading across your best trees, when your pecan crop is at risk, or when you simply want your yard to look its best, professional treatment makes a real difference.

Alpha Pest Solutions serves homeowners across the entire OKC metro, including Oklahoma City, Edmond, Norman, Midwest City, Yukon, Mustang, Del City, Bethany, Choctaw, Nichols Hills, and The Village. We use Bt-based treatments and targeted applications that control fall webworms effectively while protecting beneficial insects in your landscape.

Call or text (405) 977-0678 to schedule a free inspection. We will assess your trees, identify the problem, and recommend the most effective and responsible treatment approach for your property.