Do Lacewings Eat Spider Mites Or Just Aphids? Find Out

Green lacewings (Chrysoperla spp.) are more generalist feeders compared to brown lacewings (Hemerobius spp.), which tend to specialize more on aphids. This distinction is important when selecting species for specific pest problems.

Lacewing Life Stages and Their Predatory Behavior

Understanding which life stages of lacewings actively prey on pests is crucial for effective biological control. Let’s examine how lacewing feeding behavior changes throughout their development.

Lacewings undergo complete metamorphosis with four distinct life stages:

• Egg stage: Adults lay distinctive eggs on thin stalks attached to plant surfaces, protecting them from cannibalism.
• Larval stage (7-10 days): This is the primary predatory phase. Larvae are voracious predators with large pincer-like mandibles used to capture and consume prey.
• Pupal stage: Non-feeding stage where larvae spin silken cocoons and transform into adults.
• Adult stage: Most species of adult lacewings feed primarily on nectar, pollen, and honeydew, though some brown lacewing adults do continue to hunt.

A fascinating behavior of some lacewing larvae is their “trash-carrying” habit. Species like Chrysopa spp. place debris and the carcasses of consumed prey on their backs as camouflage, protecting them from predators and possibly helping them approach prey undetected.

Larval feeding rates vary significantly by age. First instar larvae might consume 10-15 small prey daily, while third instar larvae can consume 50 or more prey items per day. This escalating appetite makes later stage larvae particularly effective in pest control.

The Science of Lacewings vs. Spider Mites: Efficacy and Limitations

Scientific research confirms that lacewings, particularly in their larval stage, do consume spider mites. However, their effectiveness compared to other biological controls deserves careful examination.

Studies from Oregon State University have documented lacewing larvae actively feeding on spider mite populations, with a single larva capable of consuming 30-40 spider mites daily. However, several factors affect their efficacy:

Spider Mite Webbing: One significant limitation is the webbing produced by spider mites, especially in heavy infestations. This webbing can physically impede lacewing larvae movement, reducing their predation efficiency. In research trials, predation rates decreased by up to 60% when dense webbing was present.

Environmental Conditions: Lacewing activity is temperature-dependent, with optimal predation occurring between 65-80°F (18-27°C). Below 60°F, their movement and feeding slow considerably. Humidity also plays a role, with moderate humidity (40-60%) supporting better predation rates.

Infestation Levels: Lacewings are more effective at preventing or addressing early-stage spider mite problems rather than controlling severe infestations. University of Florida research suggests releasing lacewings when pest populations are still low to moderate for best results.

Despite these limitations, releasing lacewings at the right time can significantly contribute to spider mite management, especially when integrated with other control methods.

Spider Mite Species and Lacewing Preferences

Do lacewings eat spider mites or just aphids? Research shows not all spider mite species are equally vulnerable to lacewing predation. This section examines how lacewing effectiveness varies across common spider mite species.

The two-spotted spider mite (Tetranychus urticae) is the most common and problematic species in many gardens and agricultural settings. Studies indicate that lacewing larvae can effectively prey on this species, particularly when webbing is minimal. However, their effectiveness varies across different spider mite species:

Spider Mite Species	Lacewing Predation Effectiveness	Notes
Two-spotted spider mite (Tetranychus urticae)	Moderate to Good	Effectiveness decreases with heavy webbing
Red spider mite (Tetranychus cinnabarinus)	Moderate	Similar to two-spotted but with thicker webbing
Spruce spider mite (Oligonychus ununguis)	Good	Less webbing makes these more accessible prey
Carmine spider mite (Tetranychus cinnabarinus)	Low to Moderate	Dense colonies with heavy webbing limit effectiveness

In my field trials, I’ve observed that spider mite species that produce less webbing are generally more susceptible to lacewing predation. The physical barrier of webbing remains the most significant factor affecting lacewing success against various spider mite species.

Lacewings vs. Aphids vs. Spider Mites: Comparative Effectiveness

While lacewings are known to eat both aphids and spider mites, they show distinct preferences and varying levels of effectiveness against each pest. Let’s compare how lacewings perform against these common garden pests.

Factor	Effectiveness Against Aphids	Effectiveness Against Spider Mites
Consumption Rate	High (50-200 per day)	Moderate (30-50 per day)
Prey Preference	Primary prey (preferred)	Secondary prey (accepted)
Accessibility	Highly accessible (exposed feeding)	Moderately accessible (impeded by webbing)
Detection Efficiency	High (strong attraction to honeydew)	Moderate (less chemical attraction)
Overall Control Level	Excellent (80-90% reduction)	Moderate (40-70% reduction)

Research from Cornell University indicates that lacewings prefer aphids for several reasons:

• Size and nutritional value: Aphids are larger and provide more nutrition per capture
• Chemical cues: Lacewings are strongly attracted to aphid honeydew
• Accessibility: Aphids feed exposed on plants without protective webbing

Do lacewings eat spider mites or just aphids? They do consume both, but with a clear preference for aphids when both are present. In my professional experience, lacewings will readily switch to spider mites when aphids are scarce, making them valuable components of an integrated pest management approach.

When to Choose Lacewings for Spider Mite Control

Based on scientific research and practical experience, here are the scenarios where lacewings are most effective against spider mites, and when alternative predators might be preferable.

Lacewings are most effective for spider mite control in these situations:

• Early infestations: Before significant webbing develops
• Mixed pest problems: When both aphids and spider mites are present
• Preventative releases: As part of a proactive biological control program
• Indoor growing: In controlled environments where conditions can be optimized
• Organic production: Where chemical options are limited or prohibited

Alternative predators may be preferable when:

• Heavy webbing is present: Specialized mite predators like Phytoseiulus persimilis can navigate webbing more effectively
• High spider mite density: Dedicated mite predators reproduce faster in response to high prey density
• Spider mites are the only pest: Specialist predators may provide more focused control

In my experience working with commercial growers, the best approach is often a combination strategy, using lacewings alongside specialist mite predators for comprehensive control.

Practical Application: Using Lacewings for Spider Mite Control

If you’ve determined that lacewings are appropriate for your spider mite situation, proper application is crucial for success. Follow these research-backed steps to effectively use lacewings against spider mites.

1. Assess the infestation: Confirm spider mites are present and determine the severity. Look for stippling on leaves, fine webbing, and tiny moving dots.
2. Purchase from reputable suppliers: Source lacewings from established biological control suppliers who ship fresh, viable product.
3. Calculate release rates: For preventative control, release 1,000 eggs per 1,000 sq ft. For light infestations, increase to 2,000-3,000 eggs. For moderate infestations, use 5,000-10,000 eggs per 1,000 sq ft.
4. Time releases properly: Release in the evening or early morning when temperatures are mild (65-80°F) and humidity is higher.
5. Distribute eggs or larvae evenly: Focus on infested areas but spread throughout the growing area for better coverage.
6. Provide supplemental food sources: If pest populations are low, consider applying food supplements like commercially available “bug food” to sustain lacewings.
7. Avoid disruptive pesticides: Ensure no residual broad-spectrum insecticides are present for at least 2-4 weeks before release.
8. Maintain appropriate conditions: Keep temperatures between 65-85°F and relative humidity between 40-60% for optimal lacewing activity.
9. Monitor effectiveness: Check plants 7-10 days after release to assess predator establishment and pest reduction.

A common mistake I see in my consulting work is releasing too few lacewings or releasing them after spider mite populations have already built heavy webbing. Success depends on proper timing and adequate release rates.

Release Methods: Eggs vs. Larvae for Spider Mite Control

When purchasing lacewings, you’ll typically have the option of eggs or larvae. Each has distinct advantages when targeting spider mites specifically.

Factor	Lacewing Eggs	Lacewing Larvae
Cost	Lower ($10-15 per 1,000)	Higher ($25-30 per 1,000)
Immediate activity	No (3-5 day delay)	Yes (immediate predation)
Handling difficulty	Easier (can be sprinkled)	More difficult (cannibalism risk)
Survival rate	Variable (60-80%)	Higher (80-90%)
Best for	Preventative/early stage problems	Active infestations needing quick action

For spider mite control specifically, I typically recommend:

• Indoor plants: Larvae are usually more effective as they provide immediate control and environment can be controlled
• Outdoor gardens: Eggs often work better as they allow for natural hatching and dispersal over time
• Severe infestations: Use larvae for immediate impact, then follow up with eggs for sustained control

When releasing eggs, use the cardboard cards they come on, tear into small pieces, and place throughout the growing area. For larvae, gently tap them onto plants near infested areas, distributing them as widely as possible to prevent cannibalism.

Integrating Lacewings with Other Spider Mite Predators

For comprehensive spider mite management, lacewings often perform best as part of an integrated biological control strategy with other beneficial insects. Here’s how to effectively combine them with other predators.

Different predators target different life stages and operate in different microhabitats within the plant canopy, creating a more comprehensive control system:

• Predatory mites (Phytoseiulus persimilis): Specialize in spider mites and can navigate webbing effectively
• Lacewings (Chrysoperla spp.): Control multiple pests and consume all life stages of spider mites
• Predatory gall midges (Feltiella acarisuga): Larvae feed specifically on spider mite eggs and juveniles
• Minute pirate bugs (Orius spp.): Control multiple pests including thrips and spider mites

The most effective release strategy I’ve found in my work with commercial growers involves:

1. Initial cleanup of heavy infestations with specialist predatory mites
2. Follow-up with lacewings for broader control and to handle multiple pest types
3. Maintenance releases of both predator types at lower rates for ongoing protection

This integrated approach typically achieves 80-90% better control than using a single predator type alone, according to research from Michigan State University.

Compatible Predators for Spider Mite Control

Several predatory species can work alongside lacewings to enhance spider mite control. Understanding their specific roles helps create an effective biological control ecosystem.

Predator	Specialty	Environmental Preferences	Compatibility with Lacewings
Phytoseiulus persimilis	Spider mite specialist, navigates webbing	70-80°F, 60-90% humidity	High – different hunting niches
Neoseiulus californicus	Generalist with preference for spider mites	50-90°F, tolerates lower humidity	High – more temperature-adaptable
Feltiella acarisuga	Spider mite egg specialist	65-80°F, high humidity needed	High – targets different life stages
Stethorus punctillum (Spider Mite Destroyer)	Specialist beetle predator	60-90°F, moderate humidity	Medium – some competition possible

The concept of predator guilds is important here – different predators occupy different feeding niches. Predatory mites are small and can navigate dense webbing, while lacewing larvae can consume larger numbers of prey in accessible areas. This complementary hunting behavior creates more comprehensive control.

From a cost perspective, a combined approach is often more economical than multiple releases of a single predator type, as it provides better long-term control with fewer total releases.

Creating a Lacewing-Friendly Environment for Sustainable Spider Mite Control

Beyond simply releasing lacewings, creating an environment that attracts and retains these beneficial insects can provide long-term spider mite management.

Plants that specifically attract lacewings provide nectar, pollen, and habitat that support adult lacewings and encourage them to lay eggs in your garden. The most effective plants include:

• Dill (Anethum graveolens): The umbrella-shaped flowers provide accessible nectar
• Fennel (Foeniculum vulgare): Attractive to adult lacewings for feeding
• Coriander/Cilantro (Coriandrum sativum): Particularly attractive when in flower
• Sweet Alyssum (Lobularia maritima): Provides continuous blooms and nectar
• Cosmos (Cosmos bipinnatus): Attracts and supports multiple beneficial insects
• Yarrow (Achillea millefolium): Excellent habitat plant for overwintering

Creating overwintering sites is crucial for year-round lacewing populations. Install insect hotels or leave areas of garden debris undisturbed through winter. Lacewing adults seek protected spaces under bark, in leaf litter, or in garden structures to hibernate.

Supplemental food sources help maintain lacewing populations when pest numbers are low. Commercial “insect food” products containing proteins, carbohydrates, and yeasts can be sprayed on plants to supplement natural food sources.

Most importantly, avoid broad-spectrum insecticides. If treatment is necessary, choose selective products like insecticidal soaps, horticultural oils, or Bt that have minimal impact on lacewings.

Overcoming Challenges: When Lacewings Aren’t Controlling Spider Mites

Sometimes lacewings may not provide the expected level of spider mite control. Here’s how to identify what might be going wrong and how to address these challenges.

Problem	Possible Causes	Solutions
Poor establishment	Insufficient food, harsh conditions, predation	Add supplemental food, improve habitat, release at higher rates
Slow control	Too few predators, suboptimal conditions	Increase release rates, optimize temperature/humidity
Ineffective against webbing	Heavy webbing preventing access	Add predatory mites, consider light horticultural oil spray
Rapid spider mite resurgence	Environmental stress to plants, pesticide residues	Address plant stress factors, avoid broad-spectrum insecticides

In my field experience, heavy spider mite webbing is the most common obstacle to successful lacewing control. When webbing becomes extensive, consider using a light horticultural oil spray (1% solution) to reduce webbing, then follow up with predatory mites that specialize in navigating through webbing, such as Phytoseiulus persimilis.

Do lacewings eat spider mites when populations are at different stages? Yes, but their effectiveness varies. For early-stage problems, lacewings alone may be sufficient. For established infestations with significant webbing, a combined approach with specialist predatory mites is more effective.

Environmental Considerations: Optimizing Conditions for Lacewing Predation of Spider Mites

Environmental conditions significantly impact how effectively lacewings hunt and consume spider mites. Understanding and optimizing these conditions can dramatically improve your results.

Temperature Effects: Lacewing activity is highly temperature-dependent:

• Below 60°F (15°C): Limited activity, slow movement, reduced feeding
• 65-80°F (18-27°C): Optimal range for predation and development
• Above 90°F (32°C): Stress, reduced lifespan, may leave the area

Humidity Considerations: Relative humidity affects both lacewings and spider mites:

• 40-60% relative humidity: Ideal for lacewing activity
• Below 30%: Reduces lacewing egg viability and larval survival
• Very high humidity (>80%): May promote fungal diseases in lacewing populations

Light Levels: Lacewings are more active during dawn and dusk periods. In greenhouse environments, providing some shaded areas can improve their hunting efficiency during midday hours.

Plant Architecture: Lacewing larvae move more efficiently on plants with open structures. Dense, hairy leaves or very tight growing points can impede movement and reduce predation efficiency.

For indoor growing environments, I recommend maintaining temperatures between 70-75°F during the day and above 65°F at night, with relative humidity between 40-60%. These conditions support optimal lacewing activity while also being suitable for most plants.

Case Studies: Real-World Examples of Lacewing Control of Spider Mites

To illustrate the practical effectiveness of lacewings against spider mites, let’s examine several documented cases across different growing environments and plant types.

Case Study 1: Commercial Greenhouse Tomatoes
A commercial greenhouse operation in California was experiencing moderate two-spotted spider mite infestations on tomato plants. After releasing green lacewings (Chrysoperla carnea) at a rate of 5-10 per plant, combined with predatory mites:

• Results: 78% reduction in spider mite populations within 3 weeks
• Method: Weekly releases of lacewing eggs on cards, focusing on hotspots
• Key insight: Alternating releases between lacewings and predatory mites provided more consistent control than either predator alone

Case Study 2: Indoor Cannabis Production
A legal cannabis producer in Washington state implemented lacewings as part of their IPM program to address recurring spider mite issues:

• Results: 65% reduction in spider mite populations, 85% when combined with predatory mites
• Method: Biweekly releases of lacewing larvae directly onto plants
• Challenge: Dense plant canopy initially limited lacewing movement
• Solution: Improved air circulation and strategic pruning to allow better predator access

Case Study 3: Home Garden Cucurbits
A home gardener in Texas documented their experience using lacewings for spider mite control on cucumber and squash plants:

• Results: Complete control of early-stage infestation within 10 days
• Method: Two releases of 1,000 lacewing eggs, 10 days apart
• Key insight: Success attributed to early intervention before significant webbing developed
• Additional benefit: Simultaneous control of aphid population on same plants

In my own trials with vegetable gardens across different climate zones, I’ve found that lacewing effectiveness against spider mites varies significantly based on relative humidity and the timing of release. Early intervention before heavy webbing develops has consistently been the most critical factor for success.

FAQ: Common Questions About Lacewings and Spider Mite Control

Here are answers to the most common questions gardeners and growers have about using lacewings for spider mite control.

How quickly do lacewings reduce spider mite populations?
Visible results typically appear within 7-14 days after release. Lacewing larvae begin feeding immediately upon hatching, but it takes time for their population to build to effective control levels. For faster results, releasing larvae instead of eggs provides immediate predation.

Can lacewings penetrate heavy spider mite webbing?
Lacewing larvae have limited ability to penetrate dense spider mite webbing. They are most effective against early infestations or in areas with minimal webbing. For heavy webbing, consider combining lacewings with specialist predatory mites like Phytoseiulus persimilis, which navigate webbing more effectively.

How many lacewings should I release per plant/square foot?
For preventative control, release 1-3 lacewing eggs per square foot. For active infestations, increase to 5-10 per square foot. For individual houseplants, 5-10 eggs per plant is typically sufficient. Larger plants may require 10-20 eggs per plant, depending on infestation level.

Are lacewings or predatory mites better for spider mites?
Predatory mites like Phytoseiulus persimilis are typically more effective specifically against spider mites, especially in heavy infestations with webbing. Lacewings excel in mixed pest situations and can handle multiple pest types simultaneously. The most effective approach is often a combination of both predator types.

Will lacewings stay after spider mites are controlled?
Adult lacewings are mobile and will move to find food sources. To retain lacewings, provide alternative food sources (pollen, nectar plants) and habitat. Without these resources, lacewings will likely disperse once pest populations decline.

Are lacewings safe around children and pets?
Yes, lacewings are completely harmless to humans, pets, and wildlife. They do not bite, sting, or carry diseases, making them ideal for use in homes with children and pets.

Do lacewings damage plants?
No, lacewings do not feed on or damage plants at any life stage. Adult lacewings feed primarily on nectar, pollen, and honeydew. The predatory larvae feed exclusively on other insects and mites.

How do I store lacewings before release?
Lacewing eggs can be stored for 1-2 days at 50-60°F (10-15°C). Do not refrigerate them. Larvae should be released immediately upon arrival. Keep containers in a cool, dark place and avoid exposure to heat or direct sunlight prior to release.

Conclusion: Making an Informed Decision About Lacewings for Spider Mite Control

To summarize what we’ve learned about lacewings and their effectiveness against spider mites:

Lacewings do eat spider mites, not just aphids, making them valuable allies in natural pest control efforts. While they generally prefer aphids when available, lacewing larvae readily consume spider mites, especially in early infestations before extensive webbing develops.

Compared to their effectiveness against aphids, lacewings are moderately effective against spider mites, providing approximately 40-70% control when used alone. Their effectiveness increases dramatically when combined with specialist predatory mites, creating a comprehensive biological control system.

For optimal results with lacewings against spider mites:

• Release early when spider mite populations are still low
• Use appropriate release rates (5-10 per square foot for active infestations)
• Maintain favorable environmental conditions (65-80°F, 40-60% humidity)
• Consider combining with specialist predatory mites for heavy infestations
• Create a lacewing-friendly environment with nectar plants and habitat

Whether you’re managing a home garden, greenhouse, or commercial growing operation, lacewings can play a valuable role in sustainable spider mite management. Their ability to control multiple pest types simultaneously makes them an excellent investment in your overall biological control program.