Resistance of Strawberries to the Twospotted Spider Mite12

Abstract

Eighty-five strawberry cultivars and clones were evaluated for resistance to Tetranychus urticae Koch in greenhouse trials. The Del Norte clone of Fragaria chiloensis (L.) Duchesne was the most resistant, based on ratings of visible leaf damage. Of commercial-type cultivars, ‘Blakemore,’ ‘Siletz,’ ‘Stelemaster,’ and ‘WSU 1019’ showed the least damage. There were differences in mite populations on the cultivars but mite populations and leaf damage were poorly correlated. In field trials, Siletz, WSU 1019, and ‘BC 25’ showed resistance to damage. All cultivars observed were capable of supporting high populations of mites. The resistance of Del Norte was inherted by its progeny when crossed with Siletz, WSU 1019, and ‘Olympus.’