PRETRANSPLANT COLD-STORAGE OF STRAWBERRIES - EFFECTS ON PLANT VIGOR, YIELD, AND SPIDER-MITE (ACARI, TETRANYCHIDAE) ABUNDANCE

Strawberry (Fragaria x ananassa) developmental physiology is affected by temperature and photoperiod. Supplemental cold storage treatments o f daughter plants of the reproductively day-neutral 'Selva', between t heir harvest from high-elevation propagation nurseries and fall transp lant into production fields, stimulated vegetative vigor. In a 3-yr st udy, the increased vegetative vigor resulting from pretransplant suppl emental cold storage treatments reduced susceptibility to infestation by and abundance of twospotted spider mites, Tetranychus urticae Koch, during the subsequent fruit production season. Harvest date of daught er plants had an effect on the size of T. urticae populations in the f ollowing production season if the plants failed to receive adequate ve rnalization in the field during winter. Medium versus large daughter-c rown diameter at transplant produced no significant differences in sus ceptibility to spider mite infestation, or in the degree of vegetative vigor or yield. Proper manipulation of daughter-plant chilling treatm ent may enable strawberry producers to decrease plant susceptibility t o T. urticae infestation, produce optimum-sized plants, and maximize y ield.