What Do They Look Like?

spider_mites  220x136 hh
  • Tiny, eight-legged, 0.3 to 0.5 millimetre (1/50 inch) long with fine hairs on their bodies
  • They may be red, yellow or pale green in colour
  • Most spider mites spin delicate webs

Where Do I Find Them?

Look for spider mites on the undersides of the leaves of a variety of fruit and nut trees, vegetable and berry crops, and ornamental plants

Spider Mite Life Cycle

  • Spider mites are active in both winter and summer, but reproduce quickly during hot, dry weather
  • A single generation may take only seven days to go through its life cycle
  • Adult females lay eggs on host plants, which hatch into larvae
  • Spider mites feed on plants as larvae, through two nymph or immature stages, and as adults Adult females are larger than males and have rounded abdomens
  • Eggs are laid in the fall and will remain dormant during winter
  • Spider mites survive the winter by hiding in garden waste and in the cracks of tree trunks

What Does the Damage Look Like?

  • Adults, nymphs and larvae feed on the juices of plants; they do not chew leaves
  • Plant leaves turn yellow and speckled
  • With severe infestations, the edges of yellowed leaves become brown and brittle
  • Some plants may become deformed. In rare cases, plants may die

Are Spider Mites Really A Problem?

  • Most spider mite infestations cause only minimal or superficial damage to plants and trees
  • Early detection of spider mites is important
  • Check for spider mites by taking a piece of white paper or cardboard and striking some plant leaves against it
  • Test this out on several different plants in your yard
  • The mites can be seen walking slowly on the paper

What Can I Do?

Non-Pesticide Treatments

  • Spider mites will die off naturally in very hot weather or when their natural enemies (ladybugs, certain kinds of flies) appear
  • Spider mites usually do not cause long-term damage to plants or trees
  • Spray spider mites off the undersides of leaves with a strong stream of water from a spray bottle or garden hose, during spring and summer. You will have to repeat this as the mites do not die from the spraying
  • To avoid fungus on plants, spray water in the early morning so the leaves dry out during the day
  • Spray mites off plants with soapy water if the infestation is persistent in spring/summer
  • Hand-pick infested weeds and dispose in household garbage
  • Prune infested branches or leaves and dispose in household garbage

How Can I Prevent It Next Year?

  • Follow the healthy garden tips below to make sure your plants are robust and can fight off spider mites
  • Check plants for spider mites before you buy them!
  • New plants should be quarantined from other plants until you can be sure they are free of mites

Tips For A Healthy Garden

  • Enrich the soil once or twice a year with compost or other organic fertilizers.
  • Choose plants adapted to the conditions of sun or shade, moisture and soil acidity. If necessary, correct the drainage and acidity to suit the plants.
  • Plant native plants, which are adapted to the local climate. Most are easy to care for and have few pest problems.
  • Before buying plants, make sure they are healthy and free of diseases and insect pests.
  • Water deeply, but infrequently, to encourage deep rooting.
  • Cover the soil between plants and under shrubs with organic mulches. This insulates the soil, keeps in moisture and suppresses weeds.
  • Protect and attract native beneficial insect, birds and other animals.
© Image courtesy of City Green

Spider Mites Fact Sheet

Contact Us

CRD Hotline
Tel: 250.360.3030 or
1.800.663.4425 local 3030
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