Spider mite

Spider mites are tiny plant-feeding arachnids in the family Tetranychidae, which includes about 1,200 described species.

Spider mites are tiny plant-feeding arachnids in the family Tetranychidae, which includes about 1,200 described species. They are common pests of gardens, landscapes, farms, and indoor plants, where they feed on plant cells and may produce fine silk webbing. Despite their name, spider mites are not true spiders but belong to the mite group (Acari), and they are a recurring management issue in Canadian horticulture.

Taxonomy

Spider mites are arachnids in the subclass Acari and the family Tetranychidae. The family contains roughly 1,200 described species, with many species grouped among several economically important genera.

Description and behaviour

Spider mites are very small and often difficult to see with the naked eye. They commonly live on the undersides of leaves and other plant surfaces. Many species produce fine silk webbing, especially on heavily infested plants, which is one reason for the common name "spider mite."

Feeding and damage

Spider mites feed externally on plant tissue by piercing cells and sucking out their contents. Infestations can cause stippling, bronzing, leaf drop, reduced vigor, and in severe cases plant death or yield loss. They attack many cultivated and ornamental plants, including fruit trees, vines, vegetables, and houseplants.

Distribution and importance

Spider mites occur wherever suitable host plants grow and are important pests in agriculture, horticulture, and home gardening. The two-spotted spider mite, Tetranychus urticae, is widely known for its broad host range and pest status. In Canada, they are a common concern for gardeners, greenhouse operators, and farmers, especially in warm, dry conditions.