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Azalea Lace Bugs

Stephanitis pyrioides

Updated Mar 10, 2023

Make a Positive Identification

Azalea lace bugs are tiny, winged insects that feed on the lower leaf surface of azalea and rhododendron plants.
Adults and nymphs cause many white and yellow dots that damage the upper leaf surface. Leaf stippling describes the damage caused by piercing and sucking insect mouth parts.

Species: Azalea Lace Bugs

Rhododendron leaf showing pale stippling damage

Signe Danler, Oregon State University

Azalea lace bugs suck the sap, which damages leaf tissue. This causes white or yellow stippling damage on the upper leaf surface.

Species: Azalea Lace Bugs

Azalea leaf with lace bugs and fecal material

Robin Rosetta, Oregon State University

Nymphs and fecal spots are visible on the underside of an azalea leaf.

Species: Azalea Lace Bugs

Rhododendron leaves showing severe bleaching

Photo credits

Left:

Robin Rosetta, Oregon State University

Right:

Whitney Cranshaw, Colorado State University, Bugwood.org

Severe damage turns rhododendron leaves yellow (left photo) and even white (right photo).

Species: Azalea Lace Bugs

Tracy Wootten, University of Delaware, Bugwood.org

Azalea lace bug nymphs and adults feed on leaves. They are tiny. Use a magnifying glass to see them.

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LOOK-ALIKE: IRON DEFICIENCY

Species: Iron deficiency

Neil Bell, Oregon State University

Iron deficiency due to high soil pH causes yellow leaves with green veins (chlorosis). This deficiency looks similar to azalea lace bug feeding damage. Look for fecal spots on the lower surface of leaves to distinguish azalea lace bug damage.

Different risks or methods

Acidify soil pH by adding elemental sulfur to the soil. Use fertilizers specific to rhododendrons and azaleas. These methods help change the soil pH and make iron available to plants.

Azalea Lace Bugs Benefits

Azalea lace bugs are a food source for insect predators such as green lacewings.

Azalea Lace Bugs Risks

Azalea lace bugs suck sap and damage leaves.
They cause yellow stippling on the upper leaf surface, which is unattractive.
Their feeding reduces plant vigor.

Risk Card

Does it cause harm?

Adults & Children

None

Property

Some

Pets

None

Annoyance

Some

Environment

None

Action Optional

TAKE ACTION?

Minor azalea lace bug damage is unsightly. Severe damage weakens and kills plants.

Do I need to take action?

You may ignore minor damage. It could get worse each year.
Damaged leaves remain on the plant until they fall off or are removed.
For severely damaged plants, consider removing the plant. The ‘Encore’ series of azalea varieties have shown resistance to azalea lace bug feeding. Or install plants that are less prone to pest problems.

What if I do nothing?
Severe infestations may kill azalea and rhododendron bushes.

NEED HELP?

Consider a licensed pest control company. Learn How to Hire a Pest Control Company.
Your local Extension Specialist in Oregon and other states can suggest other methods.

SOLUTIONS FOR AZALEA LACE BUGS

Monitoring & Timing

Inspect plants weekly for signs of azalea lace bug starting in mid to late spring
Look for nymphs on the underside of leaves.
Begin treatment when you see them crawling. Action early in the season limits their numbers as the season progresses.

Non-chemical Methods

Encourage azalea lace bug predators such as green lacewings. Planting flowers to attract aphid predators is a preventive strategy. See Biological Pest Control Methods.
Spray azalea lace bugs off plants with a strong stream of water.

Insecticides (Insect Killers)

Insecticides effectively control azalea lace bugs when used according to the label instructions.

Method	Does it work?	Is it safe?	Recommendation
A Attract Lace Bug Predators	Effective	Low risk	Recommended
B Spray Plants with a Strong Stream of Water	Somewhat effective	Low risk	Recommended
C Insecticidal Soap, Horticultural Oil & Neem (Organic)	Effective	Moderate risk	Use if Necessary
D Broad-Spectrum & Systemic Insecticides	Effective	High risk	Use if Necessary
E If Using Insecticides, Protect Yourself & Minimize Risks
F Prevent Azalea Lace Bugs

Attract Lace Bug Predators

Non-Chemical Method

Attract Lace Bug Predators

Recommended

Natural enemies such as green lacewings feed on azalea lace bugs and other insects. The photo shows a green lacewing larva, which eats azalea lace bug.

Does it work?	Effective Natural enemies keep azalea lace bug populations in check. They don’t get rid of lace bug infestations. Tolerate minor damage. Use preventive measures for best results.
How much effort?	Moderate effort Include trees, shrubs, and flowers that attract wildlife and natural enemies in your landscape.
What's the risk?	Low risk
Possible risk of exposure or harm from chemicals	NONE

Whitney Cranshaw, Colorado State University, Bugwood.org

Green lacewing eggs are sold in containers. Scatter the eggs on rhododendron and azalea plants. Green lacewing larvae are predators of azalea lace bug and other insect pests.

Spray Plants with a Strong Stream of Water

Non-Chemical Method

Signe Danler, Oregon State University

Spray Plants with a Strong Stream of Water

Recommended

A strong stream of water directed at the lower leaf surface of infected plants removes or injures feeding insects.

Does it work?	Somewhat effective Use preventive measures for best results.
How much effort?	Moderate effort
What's the risk?	Low risk
Possible risk of exposure or harm from chemicals	NONE

Insecticidal Soap, Horticultural Oil & Neem (Organic)

Chemical Method: Use with caution

Weston Miller, Oregon State University

Insecticidal Soap, Horticultural Oil & Neem (Organic)

Use if Necessary

This group of insecticide products effectively controls azalea lace bug. Many products with these active ingredients are considered organic (derived from natural materials).
They have a lower impact on natural enemies such as ladybugs compared to other insecticide options.

Does it work?	Effective Insecticides must contact aphids to be effective. Thorough coverage of leaves and stems is required. Use preventive measures for best results.
How much effort?	Moderate effort Lift leaves and spray undersides of leaves. Insecticides in this group break down quickly (1–2 weeks). Repeat application as needed.
What's the risk?	Moderate risk Insecticides come with real risks. ALWAYS read the entire label front to back. Use a magnifying glass.
Possible risk of exposure or harm from chemicals	Using pesticides includes some amount of risk. The lowest risk comes without using pesticides. You may be exposed to a pesticide if you: Get it on your skin Breathe it in Eat or smoke afterward without washing hands Touch or eat plants that are wet with spray (you, pets, or children) Bring it inside on your shoes or clothes Follow directions closely to reduce risk.

These products are good choices to control azalea lace bugs for most situations.

Example product label with active ingredient potassium salts of fatty acids

Weston Miller, Oregon State University

The white boxes on this example Insect Killing Soap product label highlight active ingredient Potassium Salts of Fatty Acid. The label states the product “Kills Aphids … and other listed pests.”

Example product label with active ingredient mineral oil

The white boxes on this example product label highlight active ingredient Mineral Oil. The label states “Kills all stages of insects including eggs.” This product may be used to smother azalea lace bugs.

Example product label with active ingredient neem oil

Weston Miller, Oregon State University

White boxes on this example product label highlight active ingredient Neem Oil. The oil smothers insects and also harms insect pests when they feed on treated leaves.

Application Tips

Such products effectively kill lace bug adults and nymphs when used according to the label instructions.
The products pose less risk to people and the environment compared to other insecticide options.
Products must contact aphids to kill them. Thorough coverage is required.
Apply in the spring when you see azalea lace bug nymph activity. Repeat as needed.

Broad-Spectrum & Systemic Insecticides

Chemical Method: Use with caution

Weston Miller, Oregon State University

Broad-Spectrum & Systemic Insecticides

Use if Necessary

This group of products works to kill insect pests, but can also have an impact on beneficial insects such as bees and azalea lace bug predators.
The use of these products may be avoided by applying other methods before azalea lace bug populations damage plants.

Does it work?	Effective Products effectively control azalea lace bugs.
How much effort?	Moderate effort Use preventive measures for best results.
What's the risk?	High risk Insecticides come with real risks. ALWAYS read the entire label front to back. Use a magnifying glass. Broad-spectrum insecticides work against lawn insect pests, but can kill bees and beneficial insects. Insecticides can run off your site into waterways and may harm wildlife. See How to Keep Pesticides Out of Waterways.
Possible risk of exposure or harm from chemicals	Using insecticides includes some amount of risk. The lowest risk comes with using alternative methods. You may be exposed to an insecticide if you: Get it on your skin Breathe it in Eat or smoke afterward without washing hands Touch or eat plants that are wet with spray (you, pets, or children) Bring it inside on your shoes or clothes Follow directions closely to reduce risk.

Example product label with active ingredient cyfluthrin

Weston Miller, Oregon State University

The white box on the example product label highlights active ingredient cyfluthrin (a pyrethroid). The label state states “KILLS 100+ INSECTS” and shows a drawing of an aphid. A broad spectrum insecticide, this product also kills pollinators and natural enemies.

Example product label with active ingredient imidacloprid and other ingredients

Weston Miller, Oregon State University

The white box on this example product label highlights active ingredient imidacloprid (a neonicotinoid) and another ingredient. The label states “12 MONTH Insect Protection.” It could poison bees and natural enemies that feed on the nectar and pollen of treated plants.

Broad-Spectrum InsectiCides

Products must contact azalea lace bugs to kill them. Thorough coverage of the underside of leaves is required.
Apply early in the season when lace bugs are first spotted. This action reduces their numbers in future generations and lessens plant damage.
Repeat applications may be necessary.

Example Active Ingredients

Active ingredients in the pyrethroid and pyrethrins group:

Pyrethrins are natural chemicals that are toxic to insects. They are derived from chrysanthemum flowers.
Pyrethroids are human-made versions of similar chemicals. Example active ingredients include bifenthrin, cyfluthrin, deltamethrin, permethrin, resmethrin, and others.

Broad-spectrum insecticides are highly toxic to all arthropods, including natural enemies and pollinators. Killing natural enemies may lead to outbreaks of spider mites or other pests. Insecticides can wash off plants and run into storm drains and waterways. These broad-spectrum insecticides adversely affect non-target aquatic organisms.

SYSTEMIC INSECTICIDES (NEONICOTINOIDS)

Systemic insecticide products are absorbed by one plant part (e.g., stems or roots) and moved to leaves or other plant parts.
May be applied as a soil drench in spring. Adequate rain or irrigation are required to move the product through the soil to the roots.
A single application may provide season-long control when applied according to the label directions.

More About Neonicotinoids

Neonicotinoids are human-made chemicals similar to nicotine. They are toxic to insects.
Imidacloprid is an example active ingredient in this group of insecticides.

Neonicotinoid insecticides can harm pollinators and natural enemies. Following application, the poison may be found in flowers for months or years. Beneficial insects feed on the nectar and pollen. For more information, see OSU’s How to Reduce Bee Poisoning from Pesticides

If Using Insecticides, Protect Yourself & Minimize Risks

Chemical Method: Use with Caution

Brandon (@greener_30) on Unsplash

Why Is It important to Read Insecticide Labels?

They have detailed information on how to use the product correctly and legally.
They contain information on potential hazards of the product.
They provide instructions you should follow for poisonings and spills.
Following label instructions helps you to minimize the risks and maximize the benefits.

Key Safety Tips

Read the entire label front to back.
Follow the instructions.
Review the instructions even for brands you know.
Only apply the product where the label says it may be applied.
Keep all insecticides in their original container.

The Label is the Law

ALWAYS read the label before using herbicide products. The label is a legal document that provides information on how to safely use the herbicide. This helps avoid harm to human health and the environment. Using an herbicide in off-label ways is illegal. It can result in legal enforcement actions.

READ THE LABEL & Follow Instructions
It has instructions to protect you and the environment.

Labels are different for every product and they often change over time.
Use a magnifying glass if needed.
Pay attention to CAUTION, WARNING, and DANGER statements.
Pay attention to the PRECAUTIONARY STATEMENTS.
The law states you must read and follow herbicide instructions.

Protect Yourself
Eye, skin, & lung irritants

Wear gloves, safety glasses, a long-sleeve shirt, pants, socks, and shoes.
Avoid contact with eyes, skin, or clothing.
Wash hands after mixing or applying, and before eating or smoking.
Never spray directly overhead. Pay attention to wind conditions.

Protect Children & Pets
Keep out of the reach of children.

Keep children and pets away from the application area.
Remove toys and pet dishes from the area before applying insecticides. Wait until spray has dried or dust has settled.

Protect Pollinators
Many insecticides are extremely toxic to bees.

Honey bees and other pollinators are harmed by most insecticides.
Don’t spray on bees or other flying insects.
Don’t allow spray to contact blooming plants.

Avoid Wet Weather & Keep Insecticides Out of Waterways
Some insecticides are toxic to fish and aquatic invertebrates.

Don’t spray insecticides in water.
Insecticides sprayed on plants can wash off with rain and enter waterways.

Storage & Disposal

Store out of the reach of children and pets.
Store in a cool and dry place.
Never pour down any drain.
If you mix too much, apply it rather than storing it.
Don’t put pesticide containers in the trash unless instructed by the label.
Take unused insecticides to a hazardous waste facility.

Call 1-800-CLEANUP (1-800-253-2687) to find out where to dispose of pesticides.

For the Portland metro region in Oregon, contact Metro’s Recycling Information. Call 503-234-3000, email or visit Metro’s website

More about:

About Using Pesticides on School Grounds in Oregon

If using pesticides on school grounds, there are special rules in Oregon. See School Integrated Pest Management (Oregon Department of Agriculture).