Rose Rosette Found in Shreveport Area - An update
New reports of rose rosette disease were recently confirmed in commercial landscapes in the Shreveport and Bossier City area.
It is a devastating disease of roses and was first confirmed in Louisiana during fall 2015, said LSU AgCenter plant doctor Raj Singh.
All rose cultivars are susceptible, including Knock Out roses and wild multiflora roses.
“Symptoms produced by rose rosette disease are highly variable, depending on the cultivar or species of the rose and the plant’s age,” Singh said.
Infected roses produce a cluster of new shoots from a single point on the parent canes. The new shoots elongate rapidly and appear like a “witch’s broom,” Singh said.
“Infected canes produce excessive thorns that are green or red and soft in the beginning but later harden off as the disease progresses,” he said. “Presence of excessive thorns, especially on newly infected canes, is one of the most reliable symptoms to help with diagnosing rose rosette disease.”
Infected canes are sometimes thicker than parent canes. Reddening of new foliage and shoots also is associated with rose rosette disease.
“Remember, however, that these symptoms can be used to potentially recognize rose rosette disease, but positive confirmation of the disease requires molecular testing,” Singh said.
Although rose rosette disease produces unique symptoms on roses, those symptoms can be easily confused with those caused by other diseases, pests and stressors. Improper use of herbicide, for example, may result in distortion and clustering of new growth that looks like a “witch’s broom.”
Abnormal discoloration and distortion of new foliage have been associated with rose rosette disease, but feeding injury from chili thrips, a significant rose-growing issue in Louisiana, also causes similar symptoms........... Full article available:
LSU AgCenter News Article – Rose Rosette Found in NW LA (August 2018)
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