2018 ASHS Annual Conference

Genetic resistance to diseases is an ideal trait to have in plants. One crop where resistance is needed is in roses. This is because of a viral disease that is decimating the rose industry. The Rose Rosette Virus (RRV) causes the disease known as Rose Rosette Disease. This virus is vectored by a microscopic Eriophyid mite, Phyllocoptes fructiphlus. This mite feeds on roses and females overwinter on the rose plant. There is research that suggests the mite can be controlled with miticides, however treatment only prevents infection if started before mites feed on plants. Unfortunately, once the rose is infected, there is no cure. Thus, the management approach is to eliminate infected plants to avoid disease spread. Efforts to identify resistance in a rose variety have been ongoing for four years. As of now, no resistant variety has been confirmed, however through ongoing screening activities, it is hoped that a resistant variety will be identified. Over the last three years, field trials have been established in various parts of Texas to screen rose varieties. The plots were/are located in Wichita Falls (2 years), Dallas (Year 3), Farmers Branch (Year 2), Denton (Year 2), Cleburne (Year 2), and Dallas-Coit Rd. (Year 1). Approximately 160 rose varieties have been screened or are being screened through these plots. We have identified 3 roses (Bayse’s Purple, Chuckles, Caldwell Pink) that appear tolerant to the disease. These varieties have tested positive for the virus (plants from Wichita Falls plot), but through the 3 years of screening have not developed symptoms. There is also one rose, ‘Lafter’, which is being screened in 7 locations across the United States that has not yet shown symptoms.