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Showing posts from December 23, 2012

Rose Rosette Disease: No Cure

A disease alert for growers and retailers dealing in roses

Rose rosette disease (RRD)—a virus spread by airborne mites—had infected the rose. Finally, I had to throw in the trowel and dig up the plant. For this disease, there’s no cure; an infected rose is a curse to other surrounding roses.
A rose infected by RRD suddenly develops fast-growing canes, usually purple- or bronze-red, sometimes a sickly lime-green color. This sudden, odd growth is thicker than the stem it sprouts from. As the disease progresses, new canes are covered with thorns, with many stems emerging from the same place on the cane—a witch’s broom. These shoots and their thorns are soft, almost rubbery.

Leaves have bumpy or pebbly surfaces; sometimes, they seem to be more leaf-veins than leaf, as if they’ve suffered herbicide damage. (However, RRD affects only new growth, whereas an herbicide will affect both old and new growth.) Blossoms are cabbage-shaped and tiny. Often, they can’t open. The color and shape of infe…