Spider Mite Management

Identification and Life Cycle

Mites are common landscape pests that belong to the Arachnid family along with spiders and ticks–they even spin webbing.

Spider mites are the most frequently found mites in landscape settings and are nearly ubiquitous across all regions. They appear as tiny moving dots and it can be very difficult to distinguish species, which is not entirely necessary given their similar biology, damage and management.

There are two important species of spider mites which are commonly found damaging gardens and landscapes:

The two-spotted spider mite, Tetranychus urticae, may target a wide range of host species including eggplant, beans, currants, raspberries and pears. It can also occur on houseplants. Spider mites hatch from disproportionally large, round eggs laid near the leaf’s central vein from June through September. Activity will peak during the summer months and populations grow rapidly at this time. These pests reach maturity within a week and females will lay eggs a dozen at a time daily for about two weeks following mating.

The spruce spider mite, Oligonychus ununguis, targets spruce, hemlock, arborvitae & fir trees and juniper species.

Dry conditions are conducive to reproduction, growth and spread of all species of spider mites.

Spider mites cause damage by sucking cell contents from within leaves. An infestation will be apparent by visible damage. The first appearance of damage will be light stippling which will turn bronze, then chlorotic and result in premature leaf drop. Pictured below is damage to a bean plant and a juniper from spider mites.

To aid in preventing a spider mite infestation on your landscape or houseplants, assure they receive adequate water. Management can be attained with the responsible use of appropriate treatment; if you suspect your landscape is suffering from spider mites, contact your arborist immediately.