The problem with the Knock Outs isn't the rose, it's the fact that most of them are in huge mass plantings that NO ONE tends. They plant them and forget them. Oh, someone may go by in the spring and prune them down with hedge trimmers and maybe if it's really dry throw some water on them (not even that in most cases though) but they're not really cared for. So when one plant does become infected it isn't caught immediately and ripped out and burned. It stays there infecting more and spreading the disease (and the mite that carries it) to more and more places. I know several people who have seen infected plants and notified the business of the problem and still nothing was done. They aren't rose people and they don't care.

Well this morning the two links (that worked for me yesterday on my computer) today only give the first 2 pages. Fortunately I had saved the manuscript yesterday. The following from the full paper was also of interest to me: "The common rose viruses apple mosaic virus (ApMV) (synonym rose mosaic virus [RMV]) and prunus necrotic ringspot virus (PNRSV) usually express symptoms early in the season, and the plants become asymptomatic later, with no possibility to detect these viruses. In contrast, the symptoms caused by RoYMV [19] persists throughout the season, and the virus can be detected. One possible explanation could be the suppression of posttranscriptional gene silencing [37], which is reported to be manifested by the P1 [33, 40] or HC-Pro [4, 30] peptides from members of the family Potyviridae." H.Kuska comment. Thus, the temperature dependence that has been the unappreciated "monkey wrench" in some of the earlier rose virus transmission studies that were done in warm climates does not complicate the behavior here. See: http://home.roadrunner.com/~kuska/high_temperature_effect_on_pnrsv.htm Here is a link that might be useful: my temperature effect discussion

No. Dependence on that list may do harm. "Instantaneously recognizable" can't depend on those symptoms because roses react differently to RRv and symptoms change with time and exposure to (having the disesase in, and presumed titre increase) the disease. The stems and leaves are not always bright red, nor do they stay red/purple in all cultivars if they start out red. Growth may be extremely fast. Excessive thorns are not present on all infected cultivars, nor are they present on all stems. And on and on. It's a darned shame that the state extension people don't go to gardens in their own states and report what is IN their states. At one time, the extension people all reported that RRD wasn't a problem for cultivated roses. Then there was a comment unsupported by any published, juried paper, that RRD was also in the fruit trees. That, too, dropped after a year or two.

Ann, the virus has been found in Bossier City (just about on I-20). http://bestofswla.com/2015/12/03/witchs-broom/ "Bossier shares most aspects of its climate with its sister city of Shreveport. The city has a humid subtropical climate (Köppen climate classification Cfa) with hot, humid summers and mild winters. During the warmer months, the city is prone to severe thunderstorms which feature heavy rain, high winds, hail, and occasional tornadoes. The city has a slightly above average rate of tornadoes when compared to the US average.[15] Due to the flat topography of the city and the prominence of smaller waterways that are prone to backwater flooding from the Red River, the city occasionally experiences severe flooding events. A notable occurrence of severe flooding occurred in March 2016 after torrential rains caused a rapid rise of many local waterways, displacing upwards of 3500 people from their homes across the area.[16][17] Freezing and ice storms occasionally occur during the winter months." https://en.wikipedia.org/wiki/Bossier_City,_Louisiana