Key Features
- Red, deformed shoots, excessive thorns
- Rosettes form clusters
- Easily mistaken for glyphosate injury
Symptoms
Symptoms begin with with leaves, and then shoots turning progressively more red. Leaves often become deformed, crinkled, and brittle and may have mosaic symptoms in addition to the characteristic red color. Round-up herbicide damage is often mistaken for rose rosette. For high value roses, laboratory analysis (including virus testing) is recommended for a more conclusive diagnosis of rose rosette.
Biology
Over time, leaves become smaller with shortened petioles; lateral buds break and develop short, thick, red shoots. Eriophyid mites, a wingless mite, is believed to vector this virus to rose shoots, where they feed and reproduce. Females can lay up to one egg a day for about 30 days, increasing the spread of the virus. The eggs hatch in 3-4 days, and reach adulthood in approximately one week. Virus transmission occurs during periods of active growth, May through June. Symptoms of new infections often begin appearing in mid-July.
Management Recommendations
Remove and destroy ornamental roses with a confirmed diagnosis of rose rosette. Pruning roses back to reduce the overwintering mite population, and treat remaining canes with horticultural oil to kill any remaining mites. Minimize the occurrence of multiflora rose, a host of rose rosette, by eradicating any volunteers.
Effective Pesticides
Active Ingredients include: Horticultural oil (Paraffinic or superior oil) , Insecticidal soap (Potassium salt of fatty acid)
Resources
- Not satisfied with ID? Contact the Purdue Plant and Pest Diagnostic Lab
- Sign Up for the Purdue Landscape Report
