Azalea and Rhododendron Insect Pests in South Carolina

Quick Guide: Azalea and Rhododendron Insect Pests

Affected Plants: Azaleas and rhododendrons (Rhododendron spp.)
Primary Azalea and Rhododendron Pests: Azalea lace bug (Stephanitis pyrioides), rhododendron lace bug (Stephanitis rhododendri), azalea bark scale (Eriococcus azaleae), red-headed azalea caterpillar (Datana major), rhododendron borer (Synanthedon rhododendri)
Related Pests: Azalea mite (Eotetranychus clitus), southern red mite (Oligonychus ilicis)
Primary Damage Symptoms: Leaf stippling, bronzing, premature leaf drop, webbing, sap loss, branch dieback, defoliation, and tunneling in stems
Most Important Prevention Strategy: Inspect azaleas and rhododendrons regularly to detect pests and manage them before populations become severe.|Biological Controls: Lacewings, assassin bugs, spiders, predatory mites, lady beetles, thrips, and other natural enemies help suppress several pests.
Integrated Pest Management (IPM): Monitor plants regularly and use cultural and biological controls before applying pesticides.
Chemical Control: Begin with insecticidal soaps or horticultural oils when appropriate; use labeled insecticides or systemic products only when necessary and according to label directions.

Introduction

While many people think of azaleas and rhododendrons as being completely different kinds of plants, they actually belong to the same genus, Rhododendron. Some insects and related pests occur on both azaleas and rhododendrons, while others attack only one or the other.

Azaleas and rhododendrons should be inspected regularly for insects and mites. If detected early, before pest numbers reach high levels, homeowners often can physically remove the pests. In addition, when pests are immature and few in number, the less toxic pesticides such as insecticidal soaps and horticultural oils are often effective at controlling them.

This factsheet describes the most common azalea insects, rhododendron insects, and related pests found in South Carolina and explains how to identify, prevent, and manage them using integrated pest management (IPM).

Azalea Lace Bug on Azaleas

Azalea lace bug is one of the most important insect pests of azaleas in South Carolina.

Identification

Azalea lace bug (Stephanitis pyrioides) adults are about ⅛-inch long. Their highly sculptured wings give them a lacy appearance. Adults also have dark markings on the back and wings, making them difficult to see when resting on leaves.

The immature forms, called nymphs, are colorless when they first hatch but become black as they mature. Nymphs have numerous spines on their back.

Adult and immature lace bugs feed on the undersides of leaves with needle-like mouthparts that suck plant sap.

Damage and Symptoms

Lace bug damage begins when adults and nymphs feed on the undersides of leaves, causing pale-colored speckling (stippling) on the upper leaf surface.

As feeding injury becomes more severe:

• Leaves may appear white.
• Damaged leaves may drop prematurely.
• Early leaf drop can make azaleas more susceptible to some dieback diseases.
• Black, shiny insect waste and cast skins can be found on the undersides of leaves.
• The undersides of leaves often develop a characteristic “fly-specked” appearance from egg coverings and droppings.

Lace bugs overwinter (survive the winter) as eggs. Adult females insert eggs into leaf tissue and cover them with a dark, varnish-like material. There are usually three or more generations each year in South Carolina.

Prevention and Treatment

Monitoring

• Inspect the undersides of leaves regularly, especially from early spring through fall.
• Watch for stippled foliage, black droppings, cast skins, and eggs on leaf undersides.
• Treat when the first generation appears to help reduce later-season infestations.

Cultural Controls

• Plant resistant azalea cultivars when possible.

Resistant cultivars include:

• ‘Dawn’
• ‘Pink Star’
• ‘Ereka’
• ‘Cavalier’
• ‘Pink Fancy’
• ‘Dram’
• ‘Seigei’
• ‘Macrantha’
• ‘Salmon Pink’
• ‘Elsie Lee’
• ‘Red Wing’
• ‘Sunglow’
• ‘Marilee’

Biological Control

Natural enemies that help suppress lace bug populations include:

• Assassin bugs
• Lacewings
• Predaceous mites
• Spiders

These beneficial organisms may provide adequate control when lace bug populations remain low.

Chemical Control

When chemical control becomes necessary:

• Insecticidal soaps may provide control of young nymphs.
• Thorough coverage of all leaf surfaces, especially the undersides, is essential.
• Foliar sprays should be applied when the first lace bugs appear.
• A second application, 7 to 10 days later, may be needed to control newly hatched nymphs.
• Good control of the first generation (March through May) greatly reduces problems later in the season.
• Additional treatments may be needed for the second (July through August) and later (September through October) generations.

Recommended foliar insecticides include:

• Acephate
• Bifenthrin
• Cyfluthrin
• Cyhalothrin
• Malathion

Acephate is a foliar systemic insecticide that moves through the leaves to control lace bugs feeding on the undersides. The remaining insecticides are contact insecticides and must be directed onto the lower leaf surface for effective control.

As an alternative to foliar sprays, products containing imidacloprid or dinotefuran may be applied as soil treatments around the base of shrubs. These products are available as granules or concentrates and can provide season-long control of lace bugs.

When using soil-applied treatments:

• Granular products are sprinkled around the base of the shrub.
• Concentrated products are diluted with water and poured around the base of the shrub.
• Apply the amount recommended on the product label based on the height of the shrub.
• Water the soil after applying granular products to improve uptake by the plant.
• Season-long control is an advantage of these soil-applied products.

See Table 1 for products. As with all pesticides, read and follow all label directions and precautions.

Rhododendron Lace Bug on Rhododendrons

Rhododendron lace bug is a sap-feeding insect that damages rhododendron leaves in much the same way as azalea lace bug.

Identification

Rhododendron lace bug (Stephanitis rhododendri) adults are slightly larger than azalea lace bugs and are yellow. The nymphs are similar in color but are slightly larger than azalea lace bug nymphs.

Damage and Symptoms

Rhododendron lace bugs feed on the undersides of leaves using piercing-sucking mouthparts. Their feeding produces the same type of injury seen on azaleas.

Symptoms include:

• Pale stippling on the upper leaf surface
• Grayish or bleached foliage with heavy feeding
• Premature leaf drop when infestations are severe
• Black droppings and cast skins on the undersides of leaves

Prevention and Treatment

Monitoring

• Inspect the undersides of rhododendron leaves beginning in early May.
• Look for adults, nymphs, stippling, and black droppings.
• Treat when lace bugs first appear.

Biological Control

Natural enemies such as lacewings, assassin bugs, spiders, and predaceous mites may help suppress lace bug populations. Preserve these beneficial insects whenever possible.

Chemical Control

Recommended insecticides are the same as those used for azalea lace bug.

Foliar insecticides include:

• Acephate
• Bifenthrin
• Cyfluthrin
• Cyhalothrin
• Malathion

Products containing imidacloprid or dinotefuran may also be applied as soil-applied treatments around the base of shrubs for season-long control. Follow the application directions provided under Azalea Lace Bug on Azaleas and refer to Table 1 for product information.

As with all pesticides, read and follow all label directions and precautions.

Spider Mites on Azaleas and Rhododendrons

Spider mites are common sap-feeding arachnids that damage azaleas and rhododendrons in South Carolina.

Spider mites are not insects but are more closely related to spiders. Two common species found on azaleas are the azalea mite (Eotetranychus clitus) and southern red mite (Oligonychus ilicis). They may also attack rhododendrons.

Spider mites are very small and barely visible to the naked eye. They are typically found on the undersides of leaves, though in heavy infestations they may also feed on the upper surface.

Damage and Symptoms

Spider mites feed by sucking plant sap from leaves.

Symptoms include:

• Leaves changing from their normal green color to dull green
• Gray-green or bronze-green foliage during heavy infestations
• Fine webbing covering leaves when mite populations are high

The southern red mite is a “cool weather mite,” remaining active primarily during spring and fall, but becoming almost inactive during the summer and winter. Most other spider mite species develop rapidly in dry, warm weather (temperatures greater than 70°F), with populations peaking in midsummer.

Prevention and Treatment

An easy way to detect spider mites is with white paper:

1. Hold a sheet of white paper beneath several leaves.
2. Wipe or tap the undersides of the leaves onto the paper.
3. If spider mites are present, they will leave red streaks on the paper.

Cultural Controls

• Avoid unnecessary insecticide applications that can reduce populations of beneficial insects and mites.
• Monitor plants closely during periods of warm, dry weather, when most spider mites reproduce rapidly.
• Monitor in spring and fall for southern red mites, which are active during cooler weather.

Biological Control

Natural enemies usually keep spider mite populations below damaging levels. Beneficial organisms include:

• Ladybird beetles (ladybugs)
• Thrips
• Predaceous mites

Misuse of pesticides may worsen a mite problem by eliminating these natural enemies.

Chemical Control

If mite populations remain low, early-season mite infestations can often be managed with insecticidal soap or horticultural oil.

When using these products:

• Thoroughly cover both the upper and lower leaf surfaces.
• Apply horticultural oil as a 2% solution (5 tablespoons per gallon of water).
• Apply when temperatures are between 45°F and 85°F.
• Spray in the evening to slow drying and improve effectiveness.
• Do not apply horticultural oil if rainfall is expected within 24 hours.
• Test insecticidal soap on a small number of azalea plants or varieties before treating all plants.

Insecticidal soaps and horticultural oils offer no residual activity and help to conserve beneficial insect species.

Important: Do not apply horticultural oil when temperatures are above 85°F or to drought-stressed plants. Apply late in the day when no rainfall is forecast.

Important: Do not apply insecticidal soap when temperatures are above 90°F or to drought-stressed plants. Apply late in the day.

If additional control is needed:

• Tau-fluvalinate is a recommended miticide for use on azaleas.
• Alternate miticides to help reduce the chance of resistance developing.
• Bifenthrin is an alternative insecticide that also has miticidal activity.

Important: If mites have been a problem on azaleas, do not use carbaryl sprays or imidacloprid soil drenches to control other pests. Continued use of these products may lead to subsequent spidermite outbreaks.

See Table 1 for products. As with all pesticides, read and follow all label directions and precautions.

Azalea Bark Scale on Azaleas and Rhododendrons

Azalea bark scale is one of the most common scale insects that attacks azaleas and rhododendrons.

Identification

Various scales attack azaleas and rhododendrons, but one of the most common is azalea bark scale (Eriococcus azaleae).

Scales are unusual insects because their appearance varies depending on age, sex, and species.

The adult female azalea bark scale is dark red and has a long sucking mouthpart. It is hidden beneath a white, matted, waxy egg sac about 1/8 inch in length. Adult females are immobile and commonly feed in branch forks and on twigs.

The immature stage, called the crawler, is the only mobile stage. Crawlers move about the plant for a short time before settling to feed. Both adults and crawlers feed by sucking plant sap.

Damage and Symptoms

Scale insects feed on plant sap, weakening infested plants.

Signs of infestation include:

• White, cottony or waxy egg sacs on twigs and branch crotches
• Dark red females beneath the waxy covering
• Scales clustered on small branches and stems

Prevention and Treatment

Monitoring

• Inspect twigs, branch forks, and small stems regularly for adult scales and white waxy egg sacs.
• Look for crawlers during the growing season, as this is the most susceptible stage for contact insecticides.

Cultural Controls

• Scrape small infestations from the plant and discard them.
• Prune and destroy heavily infested branches.

Chemical Control

A horticultural oil spray applied in early spring, before new foliage begins to grow, will kill many over-wintering adults and eggs by smothering them.

When using horticultural oil:

• Apply as a 2% solution (5 tablespoons per gallon of water)
• Thoroughly cover branches and stems.

Important: Do not apply horticultural oil when temperatures are above 85°F or to drought-stressed plants. Apply late in the day when no rainfall is forecast.

Insecticidal soap sprays during the growing season will help control crawlers and adult soft scales, such as azalea bark scale.

Important: Do not apply insecticidal soap when temperatures are above 90°F or to drought-stressed plants. Apply late in the day.

For best results:

• Thoroughly spray leaves, twigs, and stems.
• Apply enough spray so that it drips from all plant surfaces.

Contact insecticides are effective only against crawlers.

Recommended active ingredients include:

• Acephate
• Bifenthrin
• Cyfluthrin
• Cyhalothrin
• Malathion

Products containing dinotefuran may also be applied as a soil drench. One treatment can provide control for up to one year.

See Table 1 for products. As with all pesticides, read and follow all label directions and precautions.

Red-Headed Azalea Caterpillar on Azaleas

The red-headed azalea caterpillar is a foliage-feeding caterpillar that can quickly defoliate azaleas when feeding in groups.

Identification

The red-headed azalea caterpillar (Datana major) is the larval (immature) stage of a moth.

Young caterpillars are about 3/8 inch long and are reddish- to brownish-black with white and yellow stripes. As they mature, they reach about 2 inches in length and become almost black with:

• A bright red head
• Red legs
• Broken white longitudinal stripes along the body

Damage and Symptoms

Red-headed azalea caterpillars feed in groups and may consume large amounts of foliage before they are noticed. When disturbed, they raise their heads and tails.

Symptoms include:

• Groups of caterpillars feeding together
• Chewed or missing leaves
• Partial or severe defoliation
• Most feeding damage occurring in late summer

Prevention and Treatment

Monitoring

• Inspect azaleas regularly during late summer.
• Look for groups of young caterpillars feeding on leaves.
• Treat when caterpillars are first noticed for the best control.

Cultural Controls

• Caterpillars can be removed by hand.
• They are harmless to humans, making hand removal a practical option for small infestations.

Chemical Control

If chemical control becomes necessary, treat caterpillars as soon as they are noticed.

Products containing the following active ingredients are recommended:

• Bacillus thuringiensis (B.t.)
• Spinosad
• Acephate
• Bifenthrin
• Cyfluthrin
• Cyhalothrin
• Permethrin

For best results:

• Spinosad and B.t. are most effective against small, young caterpillars.
• If the caterpillars are large, choose one of the recommended contact insecticides.

See Table 1 for products. As with all pesticides, read and follow all label instructions and precautions.

Rhododendron Borer on Rhododendrons and Azaleas

Rhododendron borer is an important wood-boring pest of rhododendrons and occasionally azaleas.

Identification

The rhododendron borer (Synanthedon rhododendri) is the larval (immature) stage of a clearwing moth.

Adult moths resemble wasps. Females lay eggs on the bark of host plants.

The borer is pale yellow with a dark head and grows to about ½ inch long. After hatching, larvae bore through the bark into the inner tissues of the plant, creating long tunnels within branches. By late fall, they enter the sapwood, where they survive the winter.

Damage and Symptoms

Rhododendron borers prefer twigs and small branches but may also infest larger branches and main stems.

Symptoms include:

• Off-color and wilted leaves on infested branches
• Early symptoms that resemble drought stress
• Stunted branch growth compared to healthy branches
• Brown, dying branches with heavy infestation
• Damage that is most noticeable in the fall

Prevention and Treatment

Monitoring

Inspect plants for wilted or discolored branches, particularly during late summer and fall.

To confirm an infestation:

• Prune wilted branches and cut them open to look for borer larvae.
• Pheromone traps (insect chemical attractants) available from garden and agricultural supply retailers attract adult male moths.
• Capturing adult males indicates that management measures are needed.

Cultural Controls

• Prune and destroy wilted or infested branches to reduce borer populations.

Chemical Control

Permethrin can be used to protect trunks and branches from newly hatched borer larvae.

For best results:

• Treat during May and June.
• Thoroughly spray trunk and branch bark.
• Repeat applications three times at 10- to 14-day intervals.

See Table 1 for products. As with all pesticides, read and follow all label instructions and precautions.

Insecticides for Managing Azalea and Rhododendron Insect Pests in the Home Landscape (Table 1)

The following active ingredients are labeled for managing selected insect and mite pests of azaleas and rhododendrons. Always verify that the product is labeled for your specific pest and ornamental plant and follow all label directions and precautions.

Active Ingredient	Example Product Names
Acephate	BioAdvanced Science-Based Solutions 2-in-1 Systemic Rose & Flower Care Granules with 6-9-6 Fertilizer Bonide Systemic Insect Control II
Bifenthrin	Hi-Yield Bug Blaster Bifenthrin 2.4 Ready to Spray Hi-Yield Bug Blaster II Bifenthrin 2.4 Ready to Spray Monterey Mite & Insect Control Monterey Mosquito Control Martin’s FLEE Ready to Use Yard Spray Ortho Outdoor Insect Killer Concentrate Ortho Bug B Gon Insect Killer for Lawns & Gardens1 Ortho BugClear Insect Killer for Lawns & Landscapes Bifen I/T Talstar P Professional Insecticide Up-Star Gold Insecticide Hi-Yield Vegetable & Ornamental Insect Control Granules Bonide Eight Insect Control Flower & Vegetable Above & Below Soil Insect Granules
Bacillus thuringiensis (Bt)	Bonide Thuricide Bacillus thuringiensis (Bt) Garden Safe Brand Bt Worm & Caterpillar Killer Monterey Bt Natural Guard by Fertilome Caterpillar Killer Spray with Bt Natural Guard by Fertilome Caterpillar Killer Spray with Bt Ready to Use Safer Brand Caterpillar Killer For Trees, Shrubs, & Vegetables Concentrate II Southern Ag Thuricide Bt Caterpillar Control Ferti-lome Dipel Dust Biological Insecticide SA-50 Southern Ag Dipel Dust
Cyfluthrin	BioAdvanced Science-Based Solutions 24 Hour Lawn Insect Killer Ready-to-Spray BioAdvanced Science-Based Solutions Complete Brand Insect Killer for Soil & Turf Ready-to-Spray I BioAdvanced Science-Based Solutions Insect Killer for Lawns Ready-to-Spray BioAdvanced Science-Based Solutions Rose & Flower Insect Killer Ready-to-Use
Dinotefuran	Gordon’s Zylam Liquid Systemic Insecticide Valent Safari 20 SG Insecticide
Horticultural oil	Bonide All Seasons Horticulture Spray Oil Ready-to-Use Bonide All Seasons Horticulture & Dormant Spray Oil Ready-to-Spray Ferti-lome Horticultural Oil Spray Monterey Horticultural Oil Concentrate Monterey Horticultural Oil RTU Safer Brand Horticultural & Dormant Spray Oil Concentrate Southern Ag Parafine Horticultural Oil Summit Year-Round Spray Oil
Imidacloprid	BioAdvanced Science-Based Solutions 12 Month Tree & Shrub Insect Control Concentrate Landscape Formula BioAdvanced Science-Based Solutions 12 Month Tree & Shrub Protect & Feed Concentrate 2-1-1 BioAdvanced Science-Based Solutions 12 Month Tree & Shrub Protect & Feed II Concentrate 2-1-1 BioAdvanced Science-Based Solutions 12 Month Tree & Shrub Protect & Feed II Ready to Use Granules 2-1-1 BioAdvanced Science-Based Solutions 12 Month Tree & Shrub Protect & Feed Ready to Use Granules 2-1-1 BioAdvanced Science-Based Solutions 2 in 1 Systemic Rose & Flower Care Ready-to-Use Granules II Bonide Annual Tree & Shrub Insect Control w/ Systemaxx Bonide Systemic Granules Insect Control Bonide Systemic Insect Spray w/ Systemaxx Ready to Spray Ferti-lome Tree & Shrub Drench Hi-Yield Systemic Insect Granules Hi-Yield Systemic Insect Spray Ready-to-Spray Martin’s Dominion Tree & Shrub Insecticide Concentrate Monterey Once A Year Insect Control II
Insecticidal soap	Bonide Insecticidal Soap Multi-purpose Insect Control Ready to Use Garden Safe Brand Insecticidal Soap Insect Killer Miracle-Gro Nature’s Care Insecticidal Soap Natria Insecticidal Soap Ready-to-Use Natural Guard by ferti-lome Insecticidal Soap Concentrate Safer Brand Insect Killing Soap Concentrate II Whitney Farms Insecticidal Soap 1
Cyhalothrin	Bonide Eight Insect Control Garden & Home II Ready to Use Cutter Backyard Bug Control Spray Concentrate Cyzmic CS Controlled Release Insecticide Martin’s Cyonara Lawn & Garden Insect Control Martin’s Cyonara Lawn & Garden Insect Control Ready-to-Spray Spectracide Triazicide Insect Killer for Lawns & Landscapes
Malathion	Bonide Malathion 50% Insect Control Gordon’s Malathion 50% Spray Hi-Yield 55% Malathion Insect Spray Martin’s Malathion 57% Ortho Max Malathion Insect Spray Concentrate Southern Ag Malathion 50% EC Spectracide Malathion Insect Spray Concentrate Tiger Brand 50% Malathion
Permethrin	Bonide Eight Insect Control Vegetable, Fruit, & Flower Concentrate Bonide Eight Yard & Garden Ready to Spray Hi-Yield 38 Plus Turf, Termite & Ornamental Insect Control Hi-Yield Lawn Garden Pet & Farm Insect Control Southern Ag Permetrol Lawn & Garden Insecticide Tiger Brand Super 10 Brand
Spinosad	Bonide Captain Jack’s Deadbug Brew Concentrate Bonide Captain Jack’s Deadbug Brew Ready to Spray Bonide Captain Jack’s Deadbug Brew Ready to Use Bonide Colorado Potato Beetle Beater Concentrate Conserve SC Turf & Ornamental Monterey Garden Insect Spray Monterey Garden Insect Spray RTU Natural Guard by ferti-lome Spinosad Bagworm, Tent Caterpillar & Chewing Insect Control Natural Guard by ferti-lome Spinosad Soap Ortho Insect Killer Tree & Shrub Concentrate Southern Ag Conserve Naturalyte Insect Control
Tau-fluvalinate	BioAdvanced Science-Based Solutions 3-in-1 Insect, Disease & Mite Control BioAdvanced Science-Based Solutions 3-in-1 Insect, Disease & Mite Control Ready-To-Use BioAdvanced Science-Based Solutions 3-in-1 Insect, Disease & Mite Control I

RTS = Ready-to-Spray (hose-end applicator)
RTU = Ready-to-Use (pre-mixed spray bottle)

Horticultural oil: Do not apply oil sprays when the temperature is above 85°F or to drought-stressed plants. Spray late in the day when no rainfall is forecast.

Insecticidal soap: Do not apply soap sprays when the temperature is above 90°F or to drought-stressed plants. Spray late in the day.

Pesticide Disclaimer: Read and follow all label directions and precautions for all pesticides.

Pesticides are updated annually. The last updates were made in 7/2026 by N. Jordan Franklin.

Originally published 10/99