ROSE ROSETTE AS WEED CONTROL
Part 1 -"does not result in the elimination of multiflora rose"
Part 2 - Maryland Augments the Spread of Rose Rosette- 2000
Part 3 - Economic Flaws of RRD as a Weed Control
"does not result in the elimination of multiflora rose" Epstein 1995.
The abstract below summarizes Dr. Abe Epstein's recommendations in 1995 about the use of Rose Rosette to kill multiflora. (It is on line at http://iisd1.iisd.ca/agri/nebraska/show.htm)
Proceedings of the Symposium - Planning for a Sustainable Future The Case of the North American Great Plains 1995
Showcase Abstracts
A. H. Epstein
Using Plant Pathogens as Biological Weed Control Agents: Rose Rosette Disease
Multiflora rose (Rosa multiflora Thunb), a thorny shrub native to Japan and other areas of northeast Asia, has naturalized over much of the eastern two-thirds of the United States. Land infested by this plant quickly becomes unsuitable for either pasture or recreational uses. Rose rosette disease, lethal to multiflora rose, is now present in most of the naturalized range of this weedy plant. The causal agent of this disease has a very narrow host range,and our research has shown that it is both effective and safe as a biological agent for the control of multiflora rose.
The disease occurs sporadically in the field and, under most circumstances, does not result in the
elimination of multiflora rose. We have found that by augmenting the natural infection occurring in the
field, the disease can be intensified in selected tracts of rose-infested land to eliminate more than 98% of the multiflora rose stand in five to six years. Ornamental rose plantings located more than one-half mile from the treated land are not subject to any greater-than-normal risk of infection from this process.
Persons interested in using this system of multiflora rose control will be expected to attend a two-hour training session (Extension). Application of this biological control system in the field will involve about two hours of labor and less than $1.50 for expendable materials per site (field, pasture, and so forth).
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Maryland Augments the Spread of Rose Rosette- 2000
I requested permission from the American Phytopathological Society to use the disease note below as
their link to it no longer works. They told me that no permission was needed as one of the authors
works for the United States Department of Agriculture and thus the note is public record. This note
appeared in Plant Disease 84(12):1344; It also appeared on line.
Natural and Augmented Spread of Rose Rosette Disease of Multiflora Rose in Maryland. P. W. Tipping,
USDA-ARS Invasive Plant Research Lab, 3205 College Ave., Ft. Lauderdale, FL; and A. B. Sindermann, Maryland Department of Agriculture, 50 Harry S. Truman Parkway, Annapolis 21401. Plant Dis. D-2000-1013-01N, 2000 (on-line). Accepted for publication 2 October 2000.
Rose rosette disease (RRD), a mite-vectored agent of unknown etiology, was first recorded on multiflora rose, Rosa multiflora Thunb. in central Maryland in 1996. This uncharacterized agent is transmitted to some members of rose family by the eriophyid mite Phyllocoptes fructiphilus Keifer, which is common on multiflora rose in Maryland (1). It is also graft-transmissible (2). In 1996, a farmer near Middletown in Frederick County observed one plant with witches'-broom and reddened shoots along a fence row and sent a sample to J. W. Amrine, Jr. at West Virginia University, for confirmation of the disease (J. W. Amrine, personal communication). During 1997, delimiting surveys around this farm failed to detect any other plant with noticeable symptoms in an area heavily infested with multiflora rose. In an attempt to augment the disease, we grafted shield buds from this plant into 10 nearby apparently healthy plants in May and again in June 1997. None of these grafts were successful. More diseased buds were removed from the original infected plant during May 1998 and grafted into another 12 plants. By June of 1999, only the graft-inoculated plants from 1998 had symptomatic shoots arising from the graft sites. During this interval, RRD was observed in sites in western Maryland near Cumberland in Allegany County (May 1997) and Hagerstown in Washington County (May 1998). Initially, the percentage of symptomatic plants at these sites was less than 10%. Surveys 12 months later indicated that approximately 50% of the plants showed symptoms of RRD. At one site, the majority of the larger multiflora rose plants had at least one dead cane and a few were completely dead. Further augmentation of RRD by grafting was conducted in May 1998 at the University of Maryland Research and Education Center in Keedysville in southern Washington County, and by June 1999 only treated plants were symptomatic. In August 1998, one multiflora rose and one ornamental rose, Rosa hybrida 'Scarlet Meidiland' Meikrotal, exhibited RRD symptoms on a farm in northern Washington County near the Pennsylvania border. We found numerous symptomatic multiflora roses in May 1999, at a farm in northern Frederick County, also near the Pennsylvania border. Symptomatic plants have been observed during 2000 in Montgomery, Carroll, and Baltimore Counties as RRD continues to spread rapidly east and north through the state. This is the first documentation of the occurrence and rate of spread of RRD in Maryland.
References: (1) W. B. Allington et al. J. Econ. Entomol. 61:1137, 1968. (2) E. A. Thomas and C. E. Scott. Phytopathology 43:218, 1953.
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Economic Flaws of RRD as a Weed Control by Larry Peck
There is a flaw with the use of RRD as a weed control - it doesn't work! This has been demonstrated
repeatedly in field tests. “In 1989 the State of West Virginia conducted tests by attempting to spread
RRD in severely R. multiflora infested pastures in the state. In five different counties in widely
separated regions, infected plants were established, grafts were made and infected mites were introduced into target R. multiflora. Since that time, the spread from these introductory sites has been very minimal.” (Amrine, Am. Rose Mar 98,p.28).
The method advocated by Iowa State is “augmentation” in which the operator field grafts diseased leaf buds onto multiple canes on the periphery of clumps of multiflora. In grafting, there is an inherent
danger of slicing your hand. If you intend to have employees do it -think about workman's comp and
disability. Dr. Abe Epstein continues to say (see above) how easy it is. HE glossed over the fact that
graft transmission of RRD is far less successful than mite transmission (Doudrick et al,1986), the grafts
may not take. In an attack on a large mass of multiflora, the loss to RRD may be off set by tip-layering, root suckering, and seed production of the remaining canes. Even the state of Iowa continues to look at herbicides (NOT bioherbicides) for multiflora control in 2002.
How long can your field stay off production: The time required to take effect is another economic
flaw of RRD as a weed control method. It has been reported that this system works in from 3-5 years
(Epstein et al, 1997). Multiflora seeds remain viable for up to 20 years and RRD infected plants still
produce seeds. If your particular fields can remain off line for half a decade, then your operation may
be so successful that they aren't needed. I've always thought profits were to be made, not postponed.
It's too labor intensive vs. results: The labor involved in “Augmentation Method” is another problem.
In a fraction of the time required to graft on infected budwood, you can wrap a chain around the bottom of the bush and pull it out by the roots with a large tractor and drag it to a burn pile. Burning has also
been used as a multiflora control method. This is something you will have to do eventually, because if RRD worked and actually killed all the multiflora bushes, you would be left with a field of dead, woody canes to get rid of. Why wait five years to burn them? With another method, like chain and tractor, the field is then immediately available for use rather than waiting five years. If the lack of maintenance that allowed multiflora infestation in the first place continues, reinfestation will occure anyhow.
If people wish to use ineffective methods and practices in their farming operations, it's usually none of my business. Generally, I'd say- go to it. In this case, however, your actions are affecting other people which brings up another flaw - civil liability.
Harm Done to the Rose Growing Community: There is no scientific research showing that Rose
Rosette Disease does not infect ornamental roses. The work at Iowa State is widely misrepresented as such, but that study as far as we can determine used very peculiar circumstance for their test roses (see Ch 8) and they would be the first to tell you that their results apply "only to conditions of their study". Since most ornamental roses are not grown "under conditions of this study" don't expect the Iowa State study to shield you from civil liability. Anyone spreading this disease is harming rose growers. Granted, RRD may have reached our area of East Tennessee eventually (or not), but it would have been long after I was dead and gone.
The argument that it would have gotten here eventually is tantamount to killing someone with a car and saying they would have died some day anyhow. The effect of speeding up the spread has denied rose growers many years of pleasure. It has also denied rose hybridizers much needed time that will be needed to develop RRD resistant cultivars. This in turn will have a dramatic effect of local and ARS membership, result in loss of a costumer base for large companies and wipe out small nurseries who can no longer ship across state lines due to RRD.
Civil Liability: In my opinion, all of the above groups have valid claims against those whose
misrepresentations or practices resulted in the spread of this disease. For that reason, any consideration
of the economics of RRD as a weed control, one must consider civil liability. There is a real possibility
that a class action lawsuit could result in massive punative damages against anybody intentionally
spreading this incurable, contagious lethal disease of roses. This is particularly true in light of the fact
that RRD may be an invasive alien pathogen rather than native as proported by Iowa State. Most of the information available to us to make that determination has been available to the general public for a long time. In my opinion, anybody contemplating the intentional release of a deadly, contagious and incurable virus had an obligation to look into the matter thoroughly before unleashing it - failure to so would clearly be negligence.
References Cited:
Amrine, J.W., Zhao,S., 1998, Research on Aerial Dispersal of Phyllocoptes fructiphilus (Acari:Eriophyidae), Vector of Rose Rosette Disease. American Rose (3):28-29.
Doudrick, R.L., Enns, W.R., Brown, M.F., and Millikan, D.F., 1986, Characteristics and Role of the Mite Plyllocoptes fructiphilus,(Acari: Eriophyidae) in the Etiology of Rose Rosette. Ent. News 97(4): 163-168.
Epstein, A.H., Hill, J.H., and Nutter, F.W., 1997. Augmentation of rose rosette disease for biocontrol of multiflora rose (Rosa multiflora). Weed Science 45:172-178.