Comments about Rose Rosette Virus
last modified December 20, 2018
by Henry Kuska
retired, Associate Professor, Department of Chemistry, University of Akron
Ph.D., Physical Chemistry
This page gives the information that I have collected from my own literature searches and from others posting on the internet. Please let me know if you feel anything is not clear or is not addressed at all, or has been challenged in the published, reviewed scientific literature as I am continually updating/modifying it as I get feedback.
Bold print in quotes does not mean that the bold print appeared in the original; the bold print was added by me (H. Kuska) for emphasis. Information in color indicates that a link is present for further information.
A poster with possible Rose Rosette Virus symptoms has been prepared by the Collin County Rose Society. It can be viewed at: http://www.collincountyrosesociety.org/pdf/rose_rosette_poster.pdf
I do not think that the average gardner can say, with certainty, that if you observe X number of symptoms, then you can be certain that you have RRV.
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Fortunately, the Federal Government is funding a program that includes testing your roses fot the virus if they deem it necessary:
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Why is molecular testing sometimes needed to be reasonably certain that the symptoms are indeed caused by rose rosette virus?
It appears that some/many "apparent" RRV infected roses may actually only have herbicide damage. In 2013, the Texas Plant Disease Diagnostic Lab received thirty-one symptomatic samples of different rose varieties that were tested for Rose Rosette Virus. Of those thirty-one samples, only ten returned with positives finds."
The above quote is from a 2014 paper presented at a meeting.
In fact, one of the Texas A and M research professionals has made the following statement (Feb 2017):
"As always, if you suspect that your rose may have rose rosette disease, please send a sample into the Texas Plant Disease Diagnostic Clinic. Many times there are other plant problems confused for RRD, and plants are taken out that may not need to be. "
https://dallasgardenbuzz.com/2017/02/14/rose-rosette-now-what/
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An independent (outside of the Federal Research Group)scientific appraisal of where the science of rose rosette virus is now is available at:
https://microbewiki.kenyon.edu/index.php/Rose_Rosette_Virus
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An aside into what is known about herbicide damage
For the home gardener, particularly in the early stages of infection the symptoms due to herbicide damage can be very similar to early rose rosette symptoms. Perhaps the following discussion of the types of herbicide damage will be useful.
The first herbicide that I will discuss is glyphosate. Glyphosate is the active ingredient of "Round-Up" type non selective plant killers. This type of product can be a problem for rose growers because of the following characteristics:
1) Overspray (drift) can damage roses.
2) Its effect on a plant is concentration dependent. (For example, at very low dosages glyphosate simply acts as a growth hormone (hormesis). ) Thus someone may say "it is not Round-Up damage, I have seen Round-Up damage and it is different." The following pictures should give the reader an idea of how variable Round-Up damage can be.
http://www.youtube.com/watch?v=NyuM5gjdx7g
AND
http://buggyrose.tripod.com/iabioticdisorders.htm
A description of possible Round-Up damage symptoms on roses is given by an article in the Marin Rose Society newsletter. I would particularly like to point out one of the possible symptoms:
"Strange looking, thickened growth, often dark red or purple in color"
I (Henry Kuska) comment: at least one Extension Plant Pathologist has stated (slide 28): that Glyphosate damage does not cause reddened new growth. Please note that the Marin Rose Society web page does NOT agree with that statement.
3) Overspray is not the only way glyphosate can reach your roses. The Round-Up can leave the roots of a treated weed, pass through the soil, and be picked up by the roots of nearby rose bushes.
http://link.springer.com/article/10.1007/s11104-007-9387-1#
According to Google Scholar (checked on Jan 1, 2016) the above article has been cited by 42 other more recent scientific papers. If anyone questions the findings in this paper, I invite he/her to check these citations for negative comments. Please inform me of your findings.
The above paper used "sandy loam" soil. This is a very common type soil sold for home garden use as it drains easily
http://www.gardenguides.com/113913-sandy-loam-soil.html
AND
This paper has 52 citations. As above, please inform me of any negative findings.
4) The glyphosate could remain bound in the soil for long time periods.
"Glyphosate [(N-(phosphonomethyl)glycine)] is a widely used herbicide and it is known to compete for the same sorption sites in soil as phosphorus. Persistence and losses of glyphosate were monitored in a field with low phosphorus status and possible correlation between glyphosate and phosphorus leaching losses was studied. Glyphosate and its metabolite AMPA (aminomethyl phosphoric acid) residues in soil samples were analyzed after a single application in autumn. Twenty months after the application the residues of glyphosate and AMPA in the topsoil (0�25 cm) corresponded to 19% and 48%, respectively, of the applied amount of glyphosate, and traces of glyphosate and AMPA residues were detected in deeper soil layers (below 35 cm). These results indicate rather long persistence for glyphosate in boreal soils."
http://www.springerlink.com/content/w1461w60366lk018/
Then, when you add fertilizer with P; the glyphosate could be released.
"The results suggest that re-mobilization of glyphosate may represent an additional transfer pathway for glyphosate to non-target plants which is strongly influenced by soil characteristics such as P fixation potential, content of plant-available iron, pH, cation exchange capacity, sand content and soil organic matter."
http://www.springerlink.com/content/t7h6601566432076/
5) Round-Up can cause problems even if sprayed last summer or fall. A quote from Roses: Cultural Practices and Weed Control: "Roses are also very sensitive to glyphosate (Roundup and many other trade names), which can be absorbed through the green stems in addition to the leaves. Glyphosate damage may appear at bud break the following spring after a summer or fall application that contacts leaves or stems; symptoms include a proliferation of small, narrow shoots and leaves."
6) Round-Up can be held in the soil in dead Round-Up treated roots and then picked up by roots that contact the dead roots. See:
This is the model that they propose to explain their experimental results:
"In most plant species, glyphosate is not readily metabolized and is preferentially translocated to young growing tissues of roots and shoots, where it can accumulate in millimolar concentrations (Reddy et al., 2004;Monsanto, personal communication). In soil-grown target plants, this non-homogeneous distribution of glyphosate within the root tissues may lead to the formation of hot spots of root residues in soils, containing high levels of glyphosate, which is subsequently released during microbial degradation of the plant material. Without a fast immobilization of glyphosate by adsorption on the soil matrix, glyphosate toxicity to non-target plants may be induced by root contact with these hot spots. The non-homogeneous distribution of glyphosate-contaminated plant material in the soil could also explain the much higher variation of the data on sunflower biomass production, shikimate accumulation and Mn-nutritional status after glyphosate application to the rye grass pre-culture as compared to direct soil application (Fig. 2 but also Tables 1 and 2, Figs. 3–5). Since toxic effects can be expected only after direct root contact of the non-target plants with one of the hot spots of glyphosate-contaminated plant residues, sunflower seedlings without contact to the hot spots remained unaffected. In contrast, direct soil application of glyphosate resulted in a homogeneous distribution and lower bio-availability due to adsorption of the herbicide over the investigated soil profile."
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The second type of herbicide damage that I will mention is due to Weed and Feed type products that contain atrazine as the active ingredient. Atrazine only kills broad leaf weeds so it is used to kill weeds in residential lawns. Unfortunately for rose growers it is very water soluble and can damage roses down hill from the application area. Is this only a possibility or has it been tested by experiment? The link below is to a paper reporting what happens to the rose Canna hybrida King Humbert when exposed to atrazine runoff.
https://journals.ashs.org/hortsci/view/journals/hortsci/32/3/article-p430A.xml
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The third type is products that contain 2,4-D + MCPA + dicamba mixtures. Some formulations of these chemicals can be more of a problem than others because of higher volatility.
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I recommend always asking if a herbicide has been used in the area (even from the year before). Even when there is reason to suspect herbicide damage, I still recommend following the "cut off the cane" route (discussed further below) as a precaution in case it actually is RRV, but also try to eliminate the source of herbicide exposure.
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Other miscellaneous topics.
Is there something in the mites salvia that acts as a cofactor in causing a rose to become infected? Another example, is it easier to infect a rose that already has an infection from another virus? These questions are asked because there have been reports that it sometimes is difficult to experimentally infect roses directly by mechanical infection (without using the mites).
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Can one save a plant by cutting off the infected cane?
If noticed early, a number of papers recommend cutting off (at ground level) the "suspected" cane. A success rate of around 50% is sometimes stated in RRV articles.
However, some/many RRV articles state that the infection is systemic (as if the virus spreads rapidly throughout the whole plant). It used to be thought that plant viruses in general were systemic. However, recent general virus research indicates that this is NOT the case. I could not find any specific RRV-roses research on this point but the fact that the "cut the cane method" does apparently sometimes work is evidence that the infection is not rapidly systemic. The rate of spread may depend on the specific variety of rose (I assume based on how good is its immune system), the time of the year (time of slow growth, low temperature or rapid growth, high temperature). I recommend the recent article by Paul Zimmerman as to how to handle possible RRV infections.
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Should you Apply a possible immune system booster?
In the last 10-20 years it has been recognized that plants have an immune system against plant viruses. The University of Florida has posted the following report:
"A preliminary study by our team showed that foliar applications of ASM at e50 mg/L, on Knock Out roses followed by budding plants with buds from Rose rosette virus-infected plants, did not produce any symptoms of the disease, as compared to drench application of ASM or non-treated controls which showed high disease severity as indicated by the Area Under Disease Progress Curve (Fig. 1; Horsfall and Barrett, 1945). Real-time RT-qPCR testing of the plants treated with foliar application of ASM further confirmed the absence of Rose rosette virus till date (>6 months from the start of the experiment; data not shown). This finding strongly indicates to the potential of ASM in protecting roses from Rose rosette virus, which may be due to the prevention of the virus movement, or replication from infected buds to healthy plants leading to no symptoms or reduced expression and thus needs to be further studied and validated. "
H.Kuska comment: ASM is Actigard it is labeled on vegetables and fruit trees, but not on roses; Syngenta, 2015.
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There are 2 other easily obtained chemicals that may help the rose fight (resist) rose rosette disease.
1) By applying hydrogen peroxide.
"In spite of the enormous information from research on genetics of plant disease resistance, the question still remains unresolved: what is directly inhibiting or killing pathogens and suppressing symptoms in resistant plants? This is particularly true for resistance to viral infections. Here we show that externally applied reactive oxygen species (ROS) such as hydrogen peroxide (H2O2) or ROS-producing (O 2·− [superoxide] and H2O2) chemical systems infiltrated into tobacco leaves 2 hours after inoculation suppress replication of Tobacco mosaicvirus (TMV) in the susceptible Samsun (nn) cultivar. This was determined by a biological and a real-time PCR method. Infiltration of leaves of the resistant Xanthi (NN) cultivar with the ROS-producing chemicals and H2O2 significantly suppressed local necrotic lesions (i.e. the hypersensitive response) after inoculation of tobacco leaves with TMV. Accordingly, an early accumulation or external application of ROS, such as O 2·− and H2O2, in tobacco may contribute to the development of resistance to TMV infection."
The above is taken from the following 2011 reviewed scientific published paper (there are other papers, this is just one example)
: http://www.akademiai.com/content/q055880253up3p57/
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2) By applying aspirin.
"Salicylic acid (SA) is an inducer of systemic acquired resistance (SAR) and could be a potential candidate in the control of plant virus diseases............................................................................The results obtained confirm that SA promotes major changes in the induction of resistance in tomato plants and suggest that treatment with exogenous SA could be considered to reduce the infections caused by PVX."
The above is taken from the following 2014 reviewed scientific published paper (there are other papers, this is just one example)
http://link.springer.com/article/10.1007/s10658-013-0333-1
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Possible protection for a valuable rose if rose rosette virus is in your area.
It is possible that a coating of Wilt-Pruf or similar antitranspirant may fool the mite to think that it did not land on a rose.
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The April 15-16, 2013 conference on rose rosette virus recommends: "Current control strategies include keeping roses in good vigor, pruning, mite control, and cultural controls such as reducing water on leaves."
H.Kuska comments:
I assume that the "good vigor" is to keep the immune system at its best. Thus, you may want to utilize known immune system boosters such as hydrogen peroxide and/or salicylic acid (home gardners normally use aspirin as a salicylic acid substitute).
"pruning" could be important in two ways. The first is that neighboring plants do not touch each other so that there is not a walking bridge available to allow infection of neighboring plants. The second is that if you prune in the spring you can be removing mite eggs.
"reducing water on leaves" may be important because the mites need water to survive. They may not be as attracted to a dry leave as to a wet one.
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Another suggestion is to plant your roses far enough apart so that root grafts cannot form.
"Ann Peck has posted the following:
" And a paper by Golino et al. discusses the transmission of rose viruses by root-to-root grafts within beds of cultivated roses. I think the Golino paper strongly suggests a third vector for the spread of RRD as we have seen some patterns of the spread of RRD in private gardens that are consistent with root to root spread.
http://nashvillerosesociety.com/nrs_wp/combating-rose-rosette/
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Further suggested reading
First. I suggest a Google search for the most recent publications concerning Rose Rosette Virus (since some articles use a title containing Rose Rosette Disease, I suggest that the search use "rose rosette" - with the quotes). After the initial search appears on the screen, click "search tools" on the right. A tab labeled "any time" will then appear on the left. Click it and a column with a choice of times will appear. Click either "past month" or "past year" to look at the recent web pages.
Second. The American Nursery and Landscape Association (ANLA) website is intended to act as a one stop resource for growers, landscapers, extension agents. and researchers to find the most up to date information about Rose Rosette Virus. Time will tell if they make good on their intention to keep their information up to date.
This is a May 2013 article that I consider relatively up to date. (I do not know if they intend to periodically update it.) http://www.preen.com/articles/another-threat-to-roses It is by a commercial company, Preen.
This link takes you to a recent "progress type report" of Professor Ioannis Tzanetakis's research group at the University of Arkansas that is studying RRV in roses:
http://news.uark.edu/articles/32272/graduate-student-working-to-combat-war-on-roses
The following youtube link https://www.youtube.com/user/AggieExtension contains links to recent videos of talks given by the rose rosette researchers involved in the federal grant (it is my understanding that this link will be used for future information also so you may want to bookmark it.
ARE ALL ROSES SUSCIPTIBLE TO ROSE ROSETTE VIRUS?
The following 2011 article discusses specific roses that appear to have some immunity to the virus: Maryland Department of Agriculture.
Another research report was recently given at a meeting: https://ashs.confex.com/ashs/2015/webprogram/Paper21683.html
"A total of 564 observations representing about 400 unique cultivars or rose species were obtained. Of these, about 50 garden rose cultivars and 10 species roses showed no RRD symptom development. The other 330 cultivars/rose species showed mild to severe RRD symptoms. "
The rose rosette Master's Thesis by Di Bello, Patrick Louis, (UNIVERSITY OF ARKANSAS, 2015, 84 pages)is available free at the following link:
http://gradworks.umi.com/16/05/1605371.html
He tested 20 roses and found one Stormy Weather completely resistant in greenhouse trials..
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A recent video covers what is now known:
http://www.wbfarmstore.net/rose-rosette-disease/
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The following link gives a very complete report (with linked references) that I highly recommend for the present status of Rose Rosette science.
https://microbewiki.kenyon.edu/index.php/Rose_Rosette_Virus
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Scientists seek public assistance in tackling rose rosette disease, see:
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For historical purposes see Ann Peck's May 2007 twelve chapter E-book at: http://www.rosegeeks.com/.
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My other rose virus sites can be reached from the following index page: