What Do They Look Like?
- 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?
- 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
© Image courtesy of City Green
- 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.