| TREATING AN INFECTED GARDEN |
| This Chapter presents experiences dealing with RRD in rose gardens. It will remain under construction. A related topic Avoidance of RRD, Chapter 12, deals with preventive measures than can be taken. Unfortunately, many people have never heard of RRD, and it is almost never mentioned in rose books. That means one can have a severely infected garden that has been infected for two, or more years before figuring out what is wrong. What should you do? At first the task seems daunting, but it’s not. Below are cases of people dealing with RRD: |
| Case 1: Our Garden northeast of Knoxville TN. |
| Case 2: A garden in Bowling Green KY. |
| Case 3: A university garden downwind from infected wild roses. |
| Case 1: The Barbarian Hords are Knocking at the Gates of Rosedom - Fighting a Holding Action: |
| I don’t think Rose Rosette Disease will be solved in my lifetime. I will continue to grow roses, but with a dose of reality. I expect to loose some roses; I hope to keep my losses to 1% a year. I am trying to learn all I can about RRD to reduce losses and protect my roses with physical barriers that slow the spread of the disease. |
| In several ways, I am fortunate. My husband Larry is interested in this disease and has helped with this whole project. There are few nearby wild roses to harbor RRD and we control much of the surrounding acreage. We can also count on the cooperation of good neighbors who own surrounding farms. We try to maintain an RRD-free cordon around our rose gardens. We cannot exclude all stray mites that may come in on gusts of wind, because we are down wind from huge stands of wild multiflora. We garden on the top of a hill, and blister mites carried by wind will drop in. |
| When I find a RRD infected plant in our rose garden, it’s rogued out and burned fast. Surrounding roses are examined and sprayed. Canes of nearby roses that a mite could have fallen onto from the infected area (canes under the infection) are also removed. (To do this hurts because I hate to remove a healthy cane, but it's a logical sacrifice). We have learned this based on observations of RRD in many gardens. This reaction removes a potential source of infection for other roses. This works for me, but may not be for everyone. If someone is surrounded by wild roses but has no control over the land, what can they do? Many people fit into this catagory. What about a public or commercial garden? With a private garden, nobody second guesses our actions. In that we are lucky. Different circumstances require different responses. |
| We have the option to burn; some folks are forbidden to burn and their landfills won’t accept yard waste. These plants should not sit around! If it's necessary to store infected canes, they should be sprayed to kill the mites, and continue to be sprayed until the canes are dead, so that mites can no longer live on them. It's important to kill the mites BEFORE their environment becomes unfavorable and they decide to move to a better environment (another rose bush). If spraying infected multiflora with an herbicide, spray it with Cygon first or at the same time so the mites won't migrate from the bush as it dies. |
| If you can't find Cygon and the sick rose is small, there is something from the mite literature that might work. The idea comes from a paper discussing sampling mites. The scientists want to count mites and don't want the mites to leave their host plant in the transit time between harvest of the plant and it being placed on a binocular microscope. I will quote this one: "Sometimes is is necessary to 'fix the mites to plant material prior to transporting them. To accomplish this, Pen and Baranowski (1990) used Breck (r) Super Hold Hair Spray to prevent mite movement on lime fruits." (T.M. Perring, C.A. Farrar, and G.N. Oldfield. 1996. Chapter 1.6.l Sampling Techniques in Eriophyoid Mites- Their Biology, Natural Enemies and Control. Elsevier Science, E.E. Lindquist, M.W. sabelis and J. Bruin, eds. p. 370) The idea is that the spray traps the mites and they can't get away. |
| Leaving a RRD-infected rose in the middle of an otherwise healthy garden is the worst course of action. Spraying the infected plant and surrounding area then rogueing out the bush is still the best course of action, perhaps with the addition of pre-emptive spraying during hot dry spells, especially in late summer, the optimum breeding season for the mites that transmit the virus. Happily, we have not gotten to the point in our garden where we feel we need pre-emptive spraying. We are relying on Intergrated Pest Management at this time. |
| Our RRD infections so far: |
| Rosa multiflora a wonderful fragrant rose growing where it caught the infection easily. (2000) |
| 'Seven Sisters' a hundred year old bush, a tragic loss fall 2000 |
| 'Charles Austin'- we saved the bush by cutting the cane off rapidly fall 2001 |
| 'Rouletti' we hope we have saved this by removing the sick cane early fall 2002 |
| R. foetida bicolor had really strange growth that died. ? hypersensitive reaction. spring 2003 |
| 'Fuschia Meidiland' we cut off the cane, disease came back, it's gone spring 2003 |
| 'Perfectly Red' sick at the bud union this spring spring 2003 |
| 'Mount Shasta' a grafted rose, it's dead fall 2003 |
| 'Mary Magdalene' grafted, rogued out spring 2005 fall 2004 |
| ''Gloire de Dijon' own root, first symptoms near root, one cut back didn't work spring 2005 |
| 'Peter Beales version of Parks Yellow Tea Scented China' spring 2005 |
| first sick out on one long cane, we cut it back, RRD came back |
| fall 2005, we took out half the bush supporting that cane and lost |
| the whole plant fall 2006 |
| 'Golden Salmon Superior' Great ownroot Polyantha; tried rmoving the sick cane fall 2005 |
| removed spring 2006 |
| 'Seven Sisters' one cane sick, removed it; two canes sick three months later , spring 2006 |
| it's gone |
| 'American Pillar' one sick cane cut off, so far rest of bush is healthy spring 2006 |
| And that's where we are as of January 2007. |
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| Case 2 - ONE STRIKE AND YOU'RE OUT |
| Dr. Kent Campbell lives near Bowling Green, Kentucky and has been living with Rose Rosette for a number of years. There are fences near him with wild multiflora and the multiflora is sick with RRD. He can't control the fences on other folks' property, but he can control the effects of the resulting RRD on his roses. He told me about his "One Strike and You're Out" rule. When he sees aberrant growth that he associates with rose rosette on a cane, he cuts that cane back to the bud union. That's strike one. Then he watches the plant. If the plant shows additional aberrant growth, it's out. He estimates that half of his infected roses recover with no additional signs of infection. He has experience and he knows what the disease looks like on the roses he grows. With what he has learned, he continues to grow roses and to enjoy them. |
| In 2001 I asked him to approve the summary above. He replied, “What you have written about me is essentially correct. However, I have mellowed just a tiny bit this spring. If the noted infection is "slight" and the bush is big and otherwise healthy, it becomes more like 3 strikes and you're out. Usually, though, the disease strikes with great force and much of the bush is covered with witches' broom and obvious abhorrent growth quickly." |
| "I have noted that if I have lost several bushes in an older bed to RRD and even if I have done all the correct things -- remove much soil and leave fallow for a year -- the disease will appear on a neighboring bush. I believe that it moves through a bed in the soil, perhaps by touching of leaves, perhaps via spider mites, watering, ....., who knows? The first major bed I built eight years ago contains 14 bushes, only five of which are original and I have cut evil sprigs from one already twice this spring.” |
| Kent Campbell May 2001 |
| In the fall of 2001, Kent fought an action to try to save a much loved bush of 'Mavrik'. 'Mavrik' is not readily available, and his plant had been an excellent rose. RRD infection appeared to be restricted to one side of the five or six year old (think BIG) plant. He decided to not only cut out the bad canes, but also the roots that supported them. His effort has been to remove the RRD-material from one side of the bush in hopes that what remains will be free of RRD. So far (February 2002) new growth on his 'Mavrik' appears normal. |
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| Case 3 -A University garden with a limited budget downwind from infected wild roses: |
| At the Lincoln Memorial University (LMU) Rose Garden in Spring of 2000, it would have accomplished little to yank out all the plants that were suspect. Even if funds were available to replace them immediately, they would have been planted in an area subject to reinfection from RRD infected wild roses in nearby fields. Bushes were planted on four foot centers (on average) and few were so mature as to touch one another. The slight reduction in plant to plant infection that would have resulted from extensive rogueing would not offset the fact that the garden would have ceased to exist as a cohesive unit. It would have degraded into a collection of individual plants still subject to infection. Immediate action was required, but was not forthcoming. The volunteer curator and his crew did what they could to keep things going and to keep roses blooming, but this is not a success story. |
| In early August 2001 we went up to Harrogate Tennessee to visit the (LMU) Rose Garden. We first went there two years earlier as volunteers to install a drip irrigation system when they started having “problems”. In retrospect, at that time I saw several roses with the distinctive “zinc deficiency” symptom indicating they had been infected with RRD for at least a year, maybe more, but in 1999, I didn't know what I was looking at. That year, we installed drip heads for 261 roses in the main garden - one for each rose. Additionally, there are a few other rose plantings on campus that we did not work on. As far as I know, there are no records kept for the garden and I can only guess at the number of roses that have died since then, been pulled out, and replaced. |
| As we watched RRD spread throughout the garden we photographed several roses repeatedly as they sickened. By mid summer 2001 the garden had deteriorated to the point where there were probably no more than twenty uninfected plants in the main garden. I would guess this is after the plantings of about sixty or seventy replacement plants since our first visit. By this point, the volunteer workers were demoralized and had lost confidence in their efforts. Their numbers dwindled and the curator was also overwhelmed by the situation. He turned the garden back to the university administration in August 2001. Comendably, it seems the university is still committed to the rose garden. Some of the fields full of multiflora have been bushhogged. Fence lines have not, however, been cleared. There were plans to replant the garden (2002) These plans have not been realized (fall, 2003). The hill where the garden was has been changed: with bulldozers and the new garden may be farther from the fields and at least some of the fields have been bushhogged a second time. Other fencelines are better tended in the vicinity of LMU. |
| Several factors lead to this failure, and we can learn from it. First, RRD had been in the garden for several years before it was diagnosed. The catch-words," We don't have Rose Rosette in east Tennessee" became a statement of fact rather than wishful thinking. In east Tennessee parley, "that dog don't hunt." Saying we didn't have it, didn't make it so. |
| The gardens where we have seen with very high loss rates( 60 - 90%) have all fallen into this catagory of non-recognition of the disease. If RRD isn't recognized as a disease, it can't be dealt with. There is the overwhelming feeling among some gardeners that any problem can be solved if enough ______ is applied. (The blank can be filled by any or all of the words: insecticide, fungicide, fertilizer, money.) None of these factors will protect a single rose bush from RRD if the conditions are favorable for a mite (that has bitten a rose infected with RRD) to land on that single rose bush. |
| First, the importance of early diagnosis can not be over emphasized. That is a main purpose of this book. |
| Second, even after it was recognized, swift action was not taken. I get the impression the curator did not appreciate, and therefore did not convey to the university, the threat that RRD posed. If he conveyed the threat, nobody listened or acted. RRD was essentially unknown in the area, so nobody had any experience with it. In any event, after being told by us, as well as by the plant pathologist at UT to act immediately to both kill the infected mites on the upwind multiflora and at the same time kill the multiflora itself (May 2000) they did nothing. (Only in the late summer of 2001 were the fields up wind (that still had huge stands of RRD infected multiflora) bush hogged and then only half the fields.) After venting our frustration to each other, we decided it was time to mind our own business and simply observe. My husband (with a military tilt to his thinking) refers to it as fighting a war on someone else's turf rather than our own. |
| Third, This lesson is based on the curator's approach of simply pruning off new cane breaks and new canes as soon as they show symptoms (as compared to the one strike & you're out above). This was and is a formula for disaster. As we learned more about the presumed spread of RRD within a plant, we found that it was in the vascular tissue of the plant. Finger pruning sick growth off did nothing to inhibit the movement of the virus-like particles in the rose canes. (We subsequently heard of a rosarian's telling a nursery in Nashville that if they finger pruned off the witches brooms on their potted roses, they could then sell the roses. I understand that the roses were sold.) |
| I also believe there may be a seasonal element to the success of one strike and you're out. If, and I emphasize If, all the nutrient flow is one directional: roots TO leaves, then cutting a cane may work. If there is a continuing flux-with nutrient interchange roots to leaves to roots on a daily basis then no amount of cutting back may work. We are currently watching our plant of 'Charles Austin' which showed RRD symptoms (Figure 1) at the tip of one cane. We cut the cane off at the base within five minutes of seeing the ugly red growth. We are closely watching the area where the cane was cut next to the soil. I estimate that the growth happened in two days. We seem to have saved the bush; two years after we saw the "rooster tail" the rose remains symptomless. |
| Click on Picture to Enlarge |
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| By not removing roses that were known to be infected and trying to allow the maximum bloom from each bush, the entire garden was lost. A garden under this much disease pressure could possibly survive, but I wouldn't even use the "one strike and you're out policy". I would immediately remove suspect plants, which is what happens in our garden (under very low disease pressure) where we have had one half of one percent RRD loss. Something we don't do in our garden, premptive spraying with Cygon, would be advisable under the high disease pressure conditions to which the LMU garden is subject. |
| Chapter 12 has been written with this garden in mind, because the LMU garden faced unique challanges. They are adjacent to Cumberland Gap National Park, so they can not count on help in multiflora reduction from the Park Service. Deer from the park present an unrelated challenge and an unsitely deer fence is not an option due to the garden's prominent location. The garden has one more unique feature that is almost unbelievable bad luck in the context of a disease carried by a wind borne vector - its wonderful historic location. LMU is located at the southeast entrance to the historic Cumberland Gap - "the Gateway to the West". This is where Daniel Boone and the early settlers before and after the American Revolution crossed into Kentucky and the Ohio Valley. It was of great strategic importance during the Civil War and is even today an important rail link through the mountains. The fabled gap serves as a great wind funnel through which prevailing winds from the northwest are compressed like air going through a giant carborator and speed up. That picks up mites and anything else and when the wind slows down, it drops its cargo of mites and dust onto the garden. That led to very high disease pressure. |
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