Cold Injury to Red Raspberries and the Effect of Premature Defoliation and Mite Damage1

Abstract

Abstract Defoliated and undefoliated red raspberry canes were subjected to freezing temperatures in December, January, and February and lateral buds were examined for injury. Raspberry plants injured by 2-spotted spider mite were also evaluated for freeze injury. Freezing tests showed that the pith in the basal portion of the buds was most susceptible to freeze damage followed in order by the pith of the cane, the vascular tissue in the base of the buds and the floral primordia. Defoliation and mite injury increased the susceptibility of the bud tissues to freeze injury and reduced starch and sugar reserves. Severe mite defoliation reduced the number of live dormant primary buds and primary laterals the following year.