Twospotted Spider Mites (Tetranychus urticae) on Strawberry (Fragaria × ananassa) Transplants, and the Potential to Eliminate Them with Steam Treatment

Abstract

The twospotted spider mite (Tetranychus urticae) is a serious pest of strawberries. The objectives of this study were to determine incidence and severity of twospotted spider mite infestations on transplants and the potential for steam to eliminate them. Mites occurred on transplants of Florida cultivars from each of eight North American nurseries from which samples were obtained, but levels were usually low (59% of samples had zero mites). Estimated complete mortality of twospotted spider mite adult females and eggs on leaf discs using steam at 48°C was 2.7 and 1.9 h, respectively; 44°C and 46°C for up to 4 h killed 20% and 60% of the mites, respectively. Based on these results, eliminating twospotted spider mites on transplants is feasible and may be valuable for improving their management in fruit-production fields.