AUGMENTATION OF ROSE ROSETTE DISEASE FOR BIOCONTROL OF MULTIFLORA ROSE (ROSA-MULTIFLORA)

Rose rosette disease, lethal to multiflora rose and indigenous to Nort h America, has been proposed as a biocontrol agent For multiflora rose , a noxious weed in the central and eastern United States. Studies in experimental plots showed that the disease can be intensified by graft ing infected shoots onto plants in established stands (i.e., augmentat ion). The rate of disease spread in augmented plots was significantly faster compared to epidemics in nonaugmented plots at 5 locations. Aug mentation provided effective control 3 to 5 yr after implementation. R isk to ornamental rose seems to be low under conditions of this study. Plots to assess risk of the disease to ornamental roses, located at d istances greater than 100 m from augmentation sites, showed no infecti on during the 3 yr of this study.