Rose Rosette Disease (RRD) in cultivated roses
Unfortunately, RRD is threatening cultivated roses including disease-resistant ones like Knock Out and Flower Carpet. All cultivated roses (shrub, hybrid tea, floribunda, grandiflora and miniature) are potentially susceptible to the disease. The disease is limited to plants in the genus Rosa. Based on research from the University of Tennessee, there are some roses which are reported to be resistant to RRD or Rose Rosette Virus (RRV). They are R. setigera, R. aricularis, R. arkansana, R. blanda, R. palustris, R. carolina, and R. spinosissima. At this point, there is no known treatment or cure for infected plants.
The mite travels with help from the wind, and clothing and equipment which have been contaminated. Females of the species overwinter on bud scales or under bark and begin to lay one egg per day for about 30 days on newly developing shoots. Eggs hatch in about four days and are at the adult stage in about one week providing the possibility of multiple generations until the fall. The transmission of RRV is most prevalent when the plants are actively growing generally between May and mid-July.
Read more at Mcall.com