Stop this virus from spreading
BE ON THE LOOKOUT Rose rosette virus starts out as a reddish coloration on the undersides of leaves, followed by a witch’s broom — a mass of increased vegetative growth that is often stunted and thorny, like at left. Symptoms can appear anytime during the growing season.
HOW IT SPREADS The disease is usually transmitted by a microscopic eriophyid mite, which is active in spring through midsummer. It can also spread by grafting or root contact with an infected plant.
FAVORITE PLANTS Wild multiflora rose (Rosa multiflora) is the favored host, but this disease has spread to cultivated roses (Rosa spp. and hybrids), too.
KEEP IT UNDER CONTROL There is no cure, and the virus will kill diseased plants within five years. Remove and destroy infected plants, including the roots and soil around the rootball. If you’re not completely confident that all debris has been cleared, it’s best to avoid planting roses in that spot again. Eliminating insect pests will also help slow the spread.