Rose Rosette DMN
 Bizarre growth and leaf color reported in the Dallas area indicates rosebushes are at risk |
A symptom of rose rosette disease is growths at the end of a shoot called a witches' broom. The stubby, soft stems have elongated leaflets and the leaves are usually red.
By MARIANA GREENE
The Dallas Morning News
magreene@dallasnews.com
Published: 20 June 2012 04:27 PM
Howard Garrett and I have received several emails from readers asking what’s wrong with their rosebushes. After Garrett, a longtime columnist for The Dallas Morning News, requested and received photos, he identified the problem as rose rosette disease.
I had not heard of it, but it disfigures and kills rosebushes. It is not a new disease, symptoms having been recognized in the United States in 1941. It was first identified in Texas in the 1990s, according to previously published reports. A tiny mite, invisible to the eye, transmits the disease, scientists know, "but they are not certain what the disease is," writes Garrett in an email. "Experts refer to it as a viral-like pathogen."
The most recognizable symptom is a growth at the end of a shoot called a witches’ broom. This growth pattern produces stubby, soft stems with elongated leaflets; stems and leaves are usually red. Leaves will become deformed, crinkled and brittle with yellow mosaics and red pigmentation. Stems may show black blotches.
Cultivated roses show symptoms of thickened, succulent stems and a proliferation of thorns. The disease causes the plant to be exceptionally susceptible to freeze damage.
University scientists and other experts contend there is no cure. Untreated roses die within two years, so gardeners are advised to remove the entire bush, including its roots. The disease, scientists say, can persist in root pieces left behind from the diseased rose.
tt says he has heard only from a few readers and listeners to his radio show about infected roses, so he does not believe RRD is common or widespread. Dr. Mike Merchant, a Texas AgriLife extension entomologist in Dallas County, blogged about digging up his own roses last summer, due to RRD, on agrilife.org/citybugs.
Garrett, however, says he has seen prescribed organic treatments cure the disease and return a diseased bush to health.
"There is certainly a different route I would try before taking this give-up approach," Garrett writes. “I don't recommend taking the plants out before trimming the damaged growth out and at least trying the Sick Tree Treatment, just as we would for diseased trees.
"I have strong anecdotal evidence that a spray of 3 percent hydrogen peroxide will cure plants infected with viruses. We have seen it work on mosaic virus on squash and curly top on tomatoes."
Cut away the diseased stems and clean the tool's blades immediately using hydrogen peroxide (never bleach). The Sick Tree Treatment should be applied throughout any rose beds.
Choose one of these formulas:
To 1 gallon of Garrett Juice Plus add 8 ounces of 3 percent hydrogen peroxide (available at drug and grocery stores), 2 ounces of orange oil, and a fatty acid product. Spray the plants thoroughly
Spray straight 3 percent hydrogen peroxide on the plants during a cool part of the day, either early morning or dusk.
Spray the commercial product ICT Organics Natural Plant Protection, according to label directions.
The reader who sent the photos sprayed her roses and now reports healthy new growth.
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