Rose Rosette Disease
Rose rosette disease was first identified in the south in 1940. Known as a killer of both wild and cultivated roses, it wasn’t always considered to be a serious threat to cultivated roses. That all changed about 10 years ago when the incidence of the disease in home gardens began to rise rapidly.
Rose rosette has been identified as a virus and is transmitted by the tiny eriphyid mite. This mite travels on wind currents and when the wind dies down, it lands on whatever is handy. If it happens to be a rose bush of any kind, the virus will show itself shortly. It is being seen more and more frequently on cultivated roses and is also thought be caused by the use of infected graft buds.
The very popular Knockout rose has been particularly hard hit, probably because of the large numbers that have been planted in recent years, all across the U.S. This virus moves quickly through a planting.
There is no cure or control for rose rosette disease and gardeners should scout their roses vigilantly, watching for these symptoms: excessive thorniness, leaf stunting and deformation, thickening of stems, red coloration of shoots and “witches brooms”. Any infected plants should be bagged before digging and removed from the landscape as soon as possible. All nearby multiflora roses should also be removed.