Damage is expressed as stippling, and bronzing of the leaves and leaf veins. Feeding is particularly damaging during the first 4 to 5 months following transplanting in fall. Mite densities of five per leaflet during this critical period of plant growth substantially reduce berry number and overall plantation yield. The highest mite populations are often observed following the peak spring fruit harvest, and this peak is typically followed by a rapid, natural decline in mite density. 20 mites per leaf later in the season.
Predators play an important role in keeping twospotted spider mite populations in check.
Subsequent innundative releases of predaceous mites may reduce twospotted mite infestations. Following releases of predator mites, it is important to monitor spider mites to determine if they are being maintained below economically injurious levels. Choose insecticides, miticides, and fungicides carefully to prevent killing the predators. Strawberry cultivars vary in susceptibility to twospotted spider mite. Vernalization directly promotes plant vigor.