Dealing with rose rosette

Rose rosette disease has long plagued nurseries and rose enthusiasts. RRD was first reported in North America in the 1940s, causing witches' broom on roses. However, it was not until 2011 that researchers at the University of Arkansas found the causal agent, which was rose rosette virus, a virus only found in roses with typical RRD symptoms.

RRV, like all viruses, requires a living host to survive. Virus movement from infected plants to new rose hosts requires the eriophyid mite as a vector. Mites acquire the virus while feeding and transmit RRV when they move to a new feeding source. The virus is also transmitted through grafting.

Symptoms of RRD depend on environmental conditions but generally appear 1­6 months after RRV­ infected mites have transmitted the virus to healthy roses. Mosaic and mottling of leaves are the earliest symptoms of infection, but these symptoms are not solely attributed to RRV as they can also be induced by other viruses infecting rose. Later in infection, newly emerging shoots have an overabundance of thorns, are dark red and tend to bunch together in a so-called witches' broom. Witches' broom and excess thorniness are additional symptoms characteristic of RRD. Flowers are malformed, and infected roses lose their aesthetic appeal and experience an overall decline in vigor that leads to plant death.

Although RRD symptoms are very characteristic, the only way to positively diagnose the disease is to send samples to the Arkansas Plant Health Clinic for a virus assay.

There are three general strategies for virus control: start with good quality material; remove virus-infected plants from the vicinity; and vector control.

The eriophyid mite is currently the only recognized natural vector of the virus, so by controlling this mite, the spread of RRD can be slowed. The mite can be eliminated with miticides, both organic and non­organic.

For other fact sheets and information visit http://www.uaex.edu.

4-H information

There are several 4-H Clubs for Garland County youths who are 5 to 19 years old. For more information on all the fun 4-H activities that are available for youths, call the Extension office at 623-6841.

Master Gardener information

Master Gardener meetings are held on the third Thursday of each month at the Elks Lodge. They're open to the public and guests are welcome. For more information, call the Extension office at 623-6841 or email Alex Dykes at [email protected].

EHC information

Are you interested in joining an existing Extension Homemakers Club? EHC is the largest volunteer organization in the state. For information on EHC, call Alison Crane at 623-684 or email her at [email protected].