Magnification of twospotted spider mites on leaf

Magnified view of twospotted spider mites. Photo: David Cappaert, Bugwood.org

Updated: January 30, 2025

Key points about mites

  • Mites are arachnids, the group to which spiders and ticks belong; they are not insects.
  • Mites are oval-shaped and tiny, usually barely visible without magnification. Body color varies, often pale or yellowish, brown, purplish, orange, or red.
  • All mites have piercing-sucking (straw-like) mouthparts.
  • Some mites feed on plants and are considered pests, while others are beneficial predators or detritivores (consumers of organic debris as nutrient recyclers). Plant-feeding mites puncture plant cells and consume their contents, and can be found indoors and outdoors. Predatory mites hunt prey like spider mites, nematodes, or juvenile insects. Detritivores help to decompose fallen plant leaves and consume algae, fungi, and bacteria.
  • Plant damage from mite feeding ranges from mild to severe. Mites can be hard to get rid of since they reproduce rapidly, use a wide range of host plants, and readily become resistant to pesticides.

Identifying mites

  • Mites are very small, with an oval or rounded shape, usually less than 1/16 of an inch long (1-2 mm). Some velvet mite species are closer to 4 mm in length, while some spider mites are less than a millimeter. Mite legs are generally easy to see with magnification.
  • Body color varies between species and ranges from near-white or greenish-yellow to tan-brown, purplish, orange, or red.
  • Mites move around by walking; they cannot jump or fly. Given their tiny size, they can also be carried on the wind. Some mites produce fine silk (like spider mite species) that they crawl on to move about the plant.
  • Leg number varies by age and species, though most mites have either six (in larvae, the youngest juvenile stage) or eight legs. Exceptions include the eriophyid mite group, which only have four legs as adults. The shorter leg-like appendages in front of the mouth between the front legs are pedipalps, a feature shared with other arachnids. They help them sense their environment, similar to insect antennae.
Drawing of a twospotted spider mite
Adult twospotted spider mite.
Illustration: John Davidson, UMD Department of Entomology

Examples of mites

Twospotted spider mites under a leaf
Twospotted spider mite
Photo: Frank Peairs, Colorado State University, Bugwood.org
Red velvet mite
Red velvet mite
Photo: Kate Redmond
Clover mite on a leaf
Clover mite
Photo: Rayanne Lehman, Pennsylvania Department of Agriculture, Bugwood.org
Magnified view of yellow eriophyid mites on a leaf
Eriophyid mite
Photo: John Davidson, UMD
Redlegged winter mites on a leaf
Red-legged winter/earth mite
Photo: HGIC

Mite look-alikes

Several small insects or arthropods might be confused with mites based on their body shape and size. Magnification may be needed to look for key differences in body structure.

  • Globular springtails
  • Scale crawlers (juveniles/immatures)
  • Thrips

Globular springtail

Appearance: Globular springtails have a rounded body shape with a distinct head. Springtails are usually slightly larger than mites, with prominent antennae (under magnification).

Behavior: Springtails prefer damp environments, commonly found in soil and less commonly found on leaves and flowers. They can jump and tend to actively run around. Found indoors and outdoors, they are rarely noticed, and do not damage plants.

 

Photo: Ernest C. Bernard, University of Tennessee, Bugwood.org

Scale crawlers (juveniles/immatures)

Appearance: Oval in shape and usually flatter-bodied than mites. Scale crawler legs are generally not as long as those of mites.

Behavior: Crawlers are associated with the larger bodies of mature scale, which may be rounded humps, rice- or oyster-shaped, or white and waxy depending on the scale species. Crawlers are mobile, but older scale insects do not move under observation.

 

Photo: Whitney Cranshaw, Colorado State University, Bugwood.org

Thrips

Appearance: Compared to eriophyid mites, thrips can be similarly pale in color (when juveniles) and have elongated bodies, but their legs are not clustered at the front of the body. Overall, thrips are larger than similar-looking mites.

Behavior: Thrips tend to crawl faster than eriophyid mites, and are capable of jumping when disturbed. Adult thrips can also fly.

 

Photo: Whitney Cranshaw, Colorado State University, Bugwood.org

Life cycle and behavior of plant-feeding mites

Feeding

  • With piercing-sucking mouthparts, plant-feeding mites puncture plant tissue and suck up the leaking cell contents. Mites generally feed on leaves and flowers (budded or unfurled), often from the underside.
  • The pale flecking/spotting resulting from injured and emptied plant cells causes damage called stippling. Heavy stippling can turn damaged leaves a light tan or silvery color. Similar damage on fruits, usually causing a bronze-brown sheen, is called russeting.
  • Broad mites and cyclamen mites inject a toxin as they feed on plants. This can cause tissues to become stiffened, brittle, contorted, or deformed, mainly in leaf and flower buds. Heavily-damaged growth points may die, and expanded leaves might bronze (turn brownish) along the central leaf vein.
  • Mite damage on outdoor plants can resemble stippling caused by sap-sucking insects like leafhoppers or lace bugs. Both indoors and outdoors, mite damage can resemble stippling caused by thrips.
  • Temperature tolerances vary. Some mite species are more active in hot weather (like twospotted spider mites) while others are adapted to cool weather (like spruce spider mites and redlegged winter mites). Cold-adapted mites pause feeding and development during hot weather and wait for the return of suitable temperatures while in a life stage that is tolerant of heat stress (for example, dormant eggs laid in soil).

Reproduction

  • Female mites can mate, but some are also capable of parthenogenesis, a form of asexual reproduction where an embryo develops from an egg without fertilization. This is one reason why mite populations can rise rapidly.
  • In a typical mite life cycle (there are exceptions), eggs hatch into larvae and then grow through two nymph stages (first protonymph, then deutonymph) before maturing into adulthood.
  • Multiple generations are produced over the course of a year, and adults can overlap with juveniles. Depending on ambient temperatures, a new generation could be produced every one to two weeks, especially between about 70 to 85℉.
  • Adults or eggs are usually the overwintering life stage outdoors. Indoors, mites can be year-round plant pests.

Host plants

Many species of mites occur in Maryland. Pest mites often feed on a wide variety of outdoor and indoor plant species: annuals, perennials, vegetables, shrubs, trees, and vines. Some mites are host-specific, only using one or a few plant species, such as the maple bladder gall mite, boxwood mite, and honeylocust mite.

Vegetables susceptible to mite outbreaks include beans, tomatoes, and cucurbits (cucumbers, pumpkins and squash, and melons), though mites can also damage herbs and many other food plants.

Commonly-affected indoor plants include species in the aroid family (Alocasia, Philodendron, Anthurium, and others), African violets, peperomias, begonias, orchids, palms, miniature roses, citrus, and herbs.

Looking for mites

Signs and symptoms help to diagnose the presence of plant-feeding mites. Signs are direct evidence of the organism, and include visible mites themselves or their byproducts and residues. For example, twospotted spider mites produce prominent, fine silken webbing. Symptoms are unusual changes in plant growth or appearance and indirect evidence of plant harm.

One monitoring technique is to place a plain sheet of white paper under foliage with stippling damage. Sharply tap the foliage to knock mites onto the paper, where they will be more visible as moving specks. Folding the paper to squish the mites makes the reddish-brown streaks a bit easier to see. When examining plant samples, a 10x magnification tool may be needed to view spider mites, and 30x magnification for broad or cyclamen mites. A microscope is necessary for clear viewing of eriophyid mites.

Signs of a mite population

Plant parts to inspect

Common feeding areas include the undersides of young leaves and areas along the main vein.

 

Photo: Natalie Hummel, Louisiana State University AgCenter, Bugwood.org
 

Silken webbing

High populations of spider mites produce prominent webbing wrapped around leaves, buds, flowers, and stems. In comparison, spider webbing is usually not as dense with such fine threads. Numerous mites will also be crawling on the silk, where it is rare for spiders to live in a communal web. (Spiders will also be larger than mites, and they do not damage plants.)

 

Photo: Whitney Cranshaw, Colorado State University, Bugwood.org
 

Shed skins

Like insects, mites molt their exoskeleton as they grow. These shed skins (exuviae) are noticeable as white grainy-looking debris or specks in webbing or on the surface of a damaged leaf, and they might be more prominent than the mites themselves. Magnification may be needed to see shed skins.

 

Photo: M. Talabac, UME
 

Plant symptoms

Low mite numbers may not cause prominent feeding damage. Abundant mites can cause stippled, deformed, or bleached-looking leaves, as well as reduced plant growth and vigor overall.

Plant damage varies depending on the mite responsible. In general:

  • Spider mites and false spider mites (also known as flat mites) cause stippling damage. Spider mites produce silk, but flat mites do not produce silk. Flat mite feeding causes leaves to look pitted or blistered; affected tissues blacken and die.
  • Eriophyid mites deform leaves or flowers, and may transmit plant viral infections (such as with rose rosette disease).
  • Broad mites and related cyclamen mites are extremely tiny and go unnoticed until feeding causes stunted new growth, bud blast (withered or unopened flower buds), and deformed foliage that can be twisted, thickened, puckered, and brittle. Affected plant stems may develop a corkier, rougher brown skin.
  • Bulb mites can spread fungi causing bulb rot, even though the mite feeding damage itself is minor; they sometimes also infest plant stems, where damage can be more significant.

Leaf and flower deformities

Leaf galls

Abnormal tissue swellings, called galls, develop around the sites of mite feeding. The mites are inside the structures and not visible. Galls may disfigure foliage, but they do not seriously affect the health of trees and shrubs. Learn more about commonly-seen mite-created galls from Ohio State University’s Bladdergall article.

Example: maple bladdergall mite galls on red maple (Acer rubrum)

 

Photo: Ronald S. Kelley, Vermont Department of Forests, Parks and Recreation, Bugwood.org
 

Leaf galls

Some galls appear as felted-looking patches, often pale, brown, or rosy-colored. These growths are called erineum. Erineum may disfigure foliage, but they do not seriously affect the health of trees and shrubs.

Example: eriophyid mite gall on river birch (Betula nigra)

 

Photo: Steven Katovich, Bugwood.org
 

Flower deformities

An eriophyid mite which feeds in coneflower blooms can cause unusual growth in the center spikes of the flower, resulting in tufted or greenish outgrowths that can be confused for symptoms of aster yellows infection. This type of feeding damage can reduce seed production. Learn more about this condition from Ohio State University’s Coneflower Rosette Mite article.

Example: coneflower rosette mite on Purple Coneflower (Echinacea purpurea)

 

Photo: M. Talabac, UME
 

Leaf deformities

Categorized as a type of “leaf roll” gall, eriophyid mites can deform the edges of leaves, creating a crinkled appearance. The leaf edges may turn brown, but this does not usually lead to defoliation, and most trees outgrow this type of damage.

Example: wavy leaf edges on black tupelo (Nyssa sylvatica)

 

Photo: Lorraine Graney, Bartlett Tree Experts, Bugwood.org
 

Leaf stunting and deformities

Young leaves that are still expanding when mites are feeding can become permanently stunted, crinkled, or curled. These symptoms might be confused with herbicide exposure injury. Look for other symptoms and signs of mites to help differentiate.

Example: tomato leaves with abnormal elongation, wrinkling, and curling due to broad mite feeding

 

Photo: Gerald Holmes, Strawberry Center, Cal Poly San Luis Obispo, Bugwood.org
 

Feeding damage color changes

Leaf stippling

Feeding damage (stippling) will be paler than healthy plant tissue. Injured tissues turn silvery or may yellow and then bronze (turn brownish) and dry out or fall off. Nutrient deficiency like chlorosis or yellowing might be confused for mite stippling damage. Look for other symptoms and signs of mites to help differentiate.

Example: bean leaf

 

Photo: Whitney Cranshaw, Colorado State University, Bugwood.org
 

Leaf stippling

Moderate levels of stippling on some plants can appear more like pale lines or scratch marks rather than a haze of pale specks.

Example: boxwood spider mite damage, which occurs on both upper and lower leaf surfaces

 

Photo: D. Clement, UME
 

Leaf browning

As mites feed and empty plant cells, the tissue dies and dries out, turning brown. Accumulated mite feeding damage first turns leaves paler (whitish or yellow) before progressing to brown.

Example: damaged phlox leaf tissue (upper side) from mite feeding on the leaf underside

 

Photo: Bruce Watt, University of Maine, Bugwood.org
 

Widespread browning and leaf loss

Needled evergreens with heavy mite damage will turn brown and drop needles. This may be confused with normal seasonal needle drop. Look for other symptoms and signs of mites to help differentiate.

Example: dwarf Alberta spruce (Picea glauca ‘Conica’) damaged by spruce spider mites

 

Photo: HGIC
 

Management tactics for plant-feeding mites

Monitor plants for pests to prevent outbreaks. Mites are best controlled promptly when found. Only use pesticides as a last resort, and try the lowest-toxicity option first.

Discourage mites

  • Outdoors, encourage predators (natural enemies) by increasing plant species and structural diversity (layers like trees, shrubs, groundcovers) in your landscape. Ensure that your landscape has sources of nectar through all growing seasons, since some predators feed on nectar as pollinators. These natural enemies are also sensitive to pesticides. Limit pesticide use to protect this natural source of sustainable pest management.
  • Avoid over-fertilizing plants, especially with nitrogen. Excess nitrogen promotes rapid, tender growth which is often more attractive to mites and other pests. Research has shown that high nitrogen levels in plant tissue can increase susceptibility to pest attacks.
  • Minimize plant stress by watering when needed and by not growing vulnerable plants in locations subjected to reflected heat or reduced air circulation, such as near a wall or pavement. Crowded plantings can also be more vulnerable to mite outbreaks and may help mites to spread more quickly.
  • Remove weeds from garden areas so they do not harbor mite populations.
  • Some plant species might be more susceptible to mite infestations than others. Select plant species or cultivars with noted levels of resistance to common pests. For example, littleleaf/Japanese boxwood (Buxus microphylla) is rarely damaged by boxwood spider mites, while European/common boxwood (Buxus sempervirens) is a preferred host.

Reduce mite abundance

The most sustainable way to intervene is guided by the principles of Integrated Pest Management (IPM). Chemicals (pesticides) are only considered as a last resort when other types of control methods fail. Indoor or outdoor plants heavily infested with mites are best cut back or removed and discarded, as it is simpler and generally cheaper than attempting treatment.

Cultural

Indoor plants: High humidity may discourage some mite species. Avoid drought stress from underwatering, which makes plants less tolerant of mite feeding.

Outdoor plants: Avoid pruning shrubs in a way that creates dense foliage layers. Shearing stimulates abundant new growth that provides more sources of food and shelter for pests like mites. Irrigate as needed to avoid drought stress during dry weather.

Mechanical

Mites are hard to see, although easy to squish (when not microscopic). You can remove some mites from leaves by rubbing them with your fingers or wiping them off with a damp cloth, or by knocking them off with a strong jet of plain water from a garden hose or sink. Trim off heavily stippled or disfigured leaves since they will not recover.

Regularly rinse dust off foliage on plants growing near exposed soil (like dirt roads or well-traveled bare pathways), since dust-coated leaves can reduce the effectiveness of natural mite predators.

Using a plain water spray from a hose to knock pests off of a plant
Photo: C. Carignan, UME

Biological

You do not need to purchase predators to eat mites on outdoor plants. Releasing lab-raised insects or predatory mites might introduce diseases or undesirable genes into the local population of natural enemies. Additionally, when released, many might disperse and leave the garden. Instead, you can attract and maintain local natural enemies through conservation practices like reducing pesticide use and incorporating a diversity of flowering plants.

Although beneficial insect supply companies sell lab-raised predators for release in greenhouses, these beneficials might not be suitable for typical indoor settings, where the humidity level is lower. Natural enemies are often sold in bulk for pest suppression in conservatories; mail-ordering such perishable items can be expensive.

If you experiment with using purchased beneficials in an enclosed space that maintains adequate humidity (like a terrarium, grow tent, or glass cabinet), you will need to periodically repeat those releases to restock the population. Natural enemy options for plant-feeding mites include minute pirate bugs (Orius), predatory mites (Phytoseiulus and Amblyseius species, among others), and a ladybug relative called the “spider mite destroyer” (Stethorus). Lacewing larvae can eat spider mites, but they are not the most effective option.

Small all-black ladybug on a leaf
Stethorus punctillum by Gilles San Martin, Flickr.com, CC BY-SA 2.0

Chemical

Insecticides rarely work on mites. Verify that the product label states that it will control or suppress mites, since using an insecticide ineffective on mites can actually make an outbreak worse. Miticides (also called acaricides) can kill mites on contact, or poison them once the chemicals are ingested with plant juices.

  • Contact miticides are the simplest and most immediately effective option. Sprays must contact the mites directly in order to work, and mites tucked underneath deformed leaves, wedged into plant crevices, or sheltered by silken webbing can be difficult to treat. Repeat applications will be necessary since missed mites can reproduce quickly. Low-toxicity active ingredients include horticultural oil and insecticidal soap.
  • Systemic miticides are absorbed into the plant sap or tissues from foliage or root applications. This category of pesticide may risk harming pollinators visiting the plant’s flowers if a plant blooms soon after treatment. How long a systemic chemical remains in the plant’s tissues can vary and is not always known.

Active ingredients that fall between contact and systemic activity include spinosad and azadirachtin. Pesticide formulations of the beneficial insect-killing fungi Beauveria bassiana or Metarhizium anisopliae are also available.

Pollinators and Pesticides

Always read and follow all label directions. Make sure the product is labeled for use on the type of plant you are treating (such as vegetables) and for the environment where it is growing (such as home gardens, or inside the home). Do not combine sprays or use alternative ingredients (home remedies like household soap or detergent).

Mite natural enemies

Several insects and predatory mites will consume plant-feeding mites, and beneficial fungi can also infect them. Become familiar with the appearance of different life stages of these insect and mite beneficials so they are not harmed by efforts to remove pest mites. Examples below note which life stage is predatory.

Ladybug larva on a leaf
Ladybugs (larvae and adults)
Photo: Matt Bertone, NC State University
Minute pirate bug on a leaf
Minute pirate bugs (nymphs and adults)
Photo: Matt Bertone, NC State University
Lacewing larva on a leaf
Lacewings (larvae)
Photo: Matt Bertone, NC State University
Magnified view of a predatory mite walking through leaf hairs
Predatory mites (larvae, nymphs, and adults)
Photo: UMD Entomology Department
Dustywing insect on a leaf
Dustywings (larvae and adults)
Photo: Whitney Cranshaw, Colorado State University, Bugwood.org

Additional resources

Twospotted Spider Mite | University of Florida

Cyclamen Mite and Broad Mite in Ornamental Plants | NC State Extension

False Spider Mites | NC State Extension

Bulb Mites | NC State Extension

References

Davidson, John A., & Michael J. Raupp. (2014). Managing Insects and Mites on Woody Plants: an IPM Approach, Third Edition. Tree Care Industry Association.

Dreistadt, Steve H. et. al. (2004) Pests of Landscape Trees and Shrubs: An Integrated Pest Management Guide, Second Edition. University of California Statewide Integrated Pest Management Program.

Gill, Stanton, & Sanderson, J. (1998). Ball Identification Guide to Greenhouse Pests and Beneficials. Ball Publishing.

Gill, Stanton, et. al. (date not listed) Total Crop Management for Greenhouse Production. Maryland Cooperative Extension.

Steiner, M.Y., and D.P. Elliott. (1987) Biological Pest Management for Interior Plantscapes, Second Edition. Alberta Environmental Centre.

 

Author: Miri Talabac, Horticulture Coordinator, HGIC, January 2025.
Reviewed by Madeline Potter, Faculty Specialist/Entomology & Integrated Pest Management, University of Maryland Extension, January 2025.

 

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