Rose rosette disease (RRD) has infiltrated North Texas and many Trophy Club rose bushes have been affected. Several medians in Town contain knock out roses that must be removed as a result of the disease. Due to the aggressive nature of RRD, infected rose bushes should be removed and destroyed in order to help eliminate further spreading.
Symptoms and Diagnosis
The earliest symptoms of rose rosette disease include a red pigmentation of the underside of leaf veins followed by sharply increased growth of vegetative shoots, which are typically more succulent than normal and colored in various shades of red. Leaves will become deformed, crinkled, and brittle with yellow mosaics and red pigmentation. As the disease progresses, leaves become very small, petioles are shortened, and most lateral buds grow producing short, intensely red shoots. The disease causes the plant to be exceptionally susceptible to freeze damage. Symptoms on cultivated roses are typically less severe than on multiflora rose. Cultivated roses show symptoms of thickened succulent stems and a proliferation of thorns.
The disease can be transmitted by grafting and by an eriophyid mite, a wingless mite that can travel passively in the wind. Transmission typically occurs between the months of May through mid-July. Symptoms from new infections usually start appearing in mid-July. In general, smaller plants go through the disease stages more quickly than larger plants. Small plants are usually killed in about 2 years while a large plant may survive for five years in a deteriorated condition.
What to do if you suspect your rose has RRD
Rose Rosette is an incurable disease that left unchecked can spread quickly to surrounding healthy roses. The only sure way to rid yourself of this disease is to remove the plant entirely, roots and all. It is also recommended that if you have a bed of roses that you remove those closest to the infected plant. Proper removal involves bagging the entire plant before attempting to remove it. Bagging will help prevent the microscopic mites from being transported inadvertently to any nearby rose bushes. Once the rose has been removed and the roots bagged, make sure that any leaves on the ground from the infected plant are also bagged. Thoroughly clean any tools used for removal with a disinfectant such as Lysol, including gardening gloves. Once the plant/plants have been safely removed from your garden, do not plant another rose in its place for at least two years. Because RRD is systemic, any pieces of root stock left behind can produce a new plant that will also be infected and thus will infect your newly planted rose bush. Look at your garden bed of roses and make sure the plants are spaced far enough apart that there is no touching of leaves, stems, or flowers. If plants are touching, dig them up and space them further apart.