Ann, that is a relatively old (1996 paper) that is discussed along with other previous papers in the 2004 New Dawn introduction. Apparently those authors, the reviewers, and the editor did not feel that the evidence up to 2004 was conclusive: "In spite of numerous studies, RRD remains somewhat enigmatic. Indeed, although many attempts have been made to isolate and characterize the causative agent, Epstein and Hill (1999) and Rohozinski et al. (2001) still consider reports on its identification to be speculative. These speculations include a phytoplasma-like organism (Gergerich and Kim 1983), a phytoplasma (Epstein et al. 1993), a virus, or virus-like agent (Di et al. 1990; Epstein and Hill 1995; Kim et al. 1995; Ahn et al. 1996; Rohozinski et al. 2001), and a mycoplasma-like organism (Doudrick 1984). Particularly impressive, however, have been the descriptions of virus-like particles (VLPs) and double membrane-bound particles (DMPs) that are associated with RRD and a variety of other plant diseases (Ahn et al. 1998; Rohozinski et al. 2001). The evidence is suggestive that these particles are the causative agent of these plant diseases. Ahn et al. (1996) actually stated that "it is believed that the DMPs are viral in nature and are the causal agents of the diseases." Nevertheless, Epstein and Hill (1995) state that "the identity of the causal agent is unknown" and "the relationship of DMPs to the infection process is unclear." Again, Epstein and Hill (1999) state, "The causal agent of RRD has not been determined." Epstein and Hill (1995, 1999) and Rohozinski et al. (2001) presented data suggesting a low probability that the causal agent is a phytoplasma-like organism. Epstein and Hill (1999) speculate that the VLPs "seem to be a response of the diseased plant rather than the causal agent itself." ------------------------------------ In Europe similar infection symptoms have been associated with phytoplasma infections. http://apsjournals.apsnet.org/doi/abs/10.1094/PDIS.2004.88.11.1283A This group of authors, reviewers, and editor also seem to indicate that the work before 2004 was not definitive: "Virus-like diseases of rose plants of uncertain aetiology have been widely distributed throughout the world (4). Symptoms include dieback, rose rosette, witches' broom, and bud proliferation. Research conducted in England (4) and the United States (1) could not reveal the etiology of the diseases." Here is a link that might be useful: Europe research

Henry, your statement "Is the pruning and cutting shears warning relevant to PNRSV in roses?" Response -- found in this paper: http://pub.jki.bund.de/index.php/JKA/article/download/605/1515 Pertinent statements from above paper quoted below: "PNRSV and ApMV transmission by seed, pollen, on cutting implements and by root grafting from infected plants to healthy plants has been reported and the results showed that root grafting is involved in the natural spread of the virus in roses (Golino et al., 2005)." Note "...and the results showed that root grafting is involved in the natural spread of the virus in roses." This means that claims of transmission via "cutting implements" were dismissed because of root grafting. Root grafting would require that roses are planted very close together, and results in contact more intimate than occurs via pruning equipment. Also: "Because the only proven means of transmission of RMD in roses is through vegetative propagation of infected buds, scion or root stocks, the use of clean and virus-tested production material is essential to improve productivity in gardens." When you pull up references that say what you want to say and post them in isolation, you are neglecting to acknowledge that those statements were later further evaluated and discounted. The paper I cited is from 2010. Any rebuttal of the above must therefore be more recent to be taken seriously. :-/ ~Christopher

Unfortunately, I can't give an update on the current conditions at Descanso. It just was too difficult & heartbreaking to continue to go there. The last time I visited the rose garden was June 2016 with Anita Clevenger. She bore witness to the sad destruction of what once was a prominent & unique Southern California destination rose garden. It was obvious that it could only be included in the pre-conference tour for the upcoming October, 2016 HRF Conference, 'No Rose Is Safe: Preserving Roses in a Challenging World', as an example of the worst that can happen to roses in a public garden. At the time of our visit, the greatly diminished collection of Alister Clark roses was struggling under the shade of the overgrown trees above them. Lammerts roses were also struggling amongst Knock Outs. There were only a couple of Dot roses left. The Polyantha beds were still there and they hadn't yet tackled the tangled mess the Centifolia beds had become. The torn up Gallica beds still had not been planted & the plowed up roses were sprouting up again from the remaining roots. Some of the newly planted roses had black spot and were virused. For Star Roses & Weeks to have donated virused roses is inexcusable. But that was two years ago & I have no idea what has happened to the garden since. Seeing as they got off to such a bad start with people who really know little about roses, I can't imagine it's gotten better. They truly have no concept of what they destroyed. Molly Malinick has the title of Rose Garden Horticulturalist there, was fresh out of school, very young but enthusiastic. To her credit she attended the conference. I hope she learned something.

I have earlier given a link to another thread where I discuss the results on neighboring roses of applying RoundUp to test roses. Since each thread will scroll off of this forum at a different rate, I feel it is appropriate to put that information into this thread. " To test for the occurrence of root grafting, experiments were conducted using the systemic herbicide Roundup®. Plants that were treated with the herbicide died as expected and approximately 50% of the adjacent, untreated Rosa multiflora ‘Burr’ plants and 10% of the adjacent untreated ‘Dr. Huey’ and ‘Sunflare’ plants showed mild herbicide toxicity symptoms. This could be explained if root grafting had occurred, allowing herbicide to move through the vascular connection between plants. " In the full paper the experimental conditions were given. "The Round-up tests utilized 470 multiflora plants, 148 plants of Dr. Huey, and 98 plants of Sunflare. The multiflora and Dr. Huey were planted approximately 11.8 inches apart (H.Kuska comment: it was not clear to me if they were mixed in the same row or in different rows). The Sunflare plants were planted 3.3 feet apart in rows. Roundup was applied to every other plant. The treated plants all died. About 50% of the multiflora plants showed roundup symptoms. 10 % of the Dr. Huey and 10% of the Sunflare plants showed symptoms." --------------------------------------------------------------------------------------- I would expect that 3.3 feet apart would not be uncommon in many home rose gardens. I cannot post the complete paper because it is copyrighted. However, I can send e-mail copies to a limited number of individual requests under the educational exclusion. My e-mail address is: kuska@neo.rr.com The abstract is at: http://www.actahort.org/members/showpdf?booknrarnr=751_26 -------------------------------------------------------------------------------------- Even the RoundUp label acknowledges that root grafting is a known problem: This is the instruction from the Round-Up label for cut stump applications: "Apply this product using suitable equipment to ensure coverage of the entire cambium. Cut trees or resprouts close to the soil surface. Apply a 50 to 100 percent solution of this product to the freshly cut surface immediately after cutting. Delays in application may result in reduced performance. For best results, applications should be made during periods of active growth and full leaf expansion. PRECAUTIONS, RESTRICTIONS: DO NOT MAKE CUT STUMP APPLICATIONS WHEN THE ROOTS OF ADJACENT DESIRABLE TREES MAY BE GRAFTED TO THE ROOTS OF THE CUT STUMP. INJURY RESULTING FROM ROOT GRAFTING MAY OCCUR IN ADJACENT TREES. Some sprouts, stems, or trees may share the same root system. Adjacent trees having a similar age, height and spacing may signal shared roots. Whether grafted or shared, injury is likely to occur to non-treated stems/trees when one or more trees sharing common roots are treated." http://aggie-horticulture.tamu.edu/syllabi/325/schedule/Pest%20Management/Chemical%20Application%20&%20Safety/Roundup%20Original.pdf --------------------------------------------------------------------------