Resistance of Red Raspberry and Other Rubus Species to Twospotted Spider Mite (Acari: Tetranychidae)

Clones of red raspberry, Rubus idaeus L., and other Rubus species were tested in the greenhouse for resistance to the twospotted spider mite, Tetranychus urticae Koch. The red raspberry advanced selection, WSU 968, R. parvifolius ‘Cherry’, and Dormanred (1/4 R. idaeus , 3/4 R. parvifolius ) were the most resistant clones. Red raspberry ‘Willamette’, ‘Meeker’, and ‘Haida’ were defoliated by mid August, whereas the resistant Rubus clones were still green and appeared healthy. WSU 968 and Cherry transmitted the resistance to their progeny when crossed with red raspberry clones.