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Rose Rosette Disease

Rose Rosette Disease. Contagious Fatal Sneaky. What is it?. Uhhh . . . We don’t know. ?. Disease (It could be . . .). A virus or virus like particle A sequence of single or double stranded RNA Electron Micrograph studies . . . . . . nothing conclusive. Disease What does it infect?.

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Rose Rosette Disease

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  1. Rose Rosette Disease Contagious Fatal Sneaky

  2. What is it? • Uhhh . . . We don’t know. ?

  3. Disease (It could be . . .) • A virus or virus like particle • A sequence of single or double stranded RNA • Electron Micrograph studies . . . . . . nothing conclusive

  4. Disease What does it infect? • Most native roses are susceptible as well as R. multiflora and all cultivated rose species. • The result of RRD infection is DEATH!!!!!

  5. Origin of RRD Rosa multiflora • Introduced to N. America in late 1700’s for gardens and cultivar rootstocks.

  6. Rosa multiflora • Spread by the Government for . . . • cattle barriers

  7. Rosa multiflora • Spread by the Government • cattle barriers

  8. Rosa multiflora • Spread by the Government • cattle barriers • stop erosion • create wildlife habitats • crash barriers for highways

  9. Origin of RRD Rosa multiflora • OOPS!!!!! (Big Mistake) • Rosa multiflora now classified as an invasive species: • Very hardy • Very promiscuous • Impossible (nearly) to clear • Each hip contains thousands of seeds Gee . . . How can we kill this STUFF?!

  10. RRD! • First identified as “Witches’ Broom” in the 1940’s in Manitoba, Canada. • In late 90’s, RRD was spread mechanically by the enemies of Rosa multiflora (i.e. government funded scientists researching for a biocontrol) Multiflora stands = Reservoirs for RRD

  11. Known areas of RRD infection (2002)

  12. How does it get around? ^ • Disease transmitted by eriophyoid mite microscopic! Phil ! Phyllocoptes fructiphilus

  13. Dormancy/ winter rest in roses • Decrease in light triggers shutdown of chlorophyll production in leaves • As leaf shuts down, the stomata close • Upward water movement ceases • Free water binds to starches to form sugars called colloids (a.k.a. bound water) • Bound water acts as antifreeze, protecting the canes from drying out over winter • the bigger the plant cells, the more bound water is stored.

  14. Stages of Infection Phil transmits RRD when he bites the rose. Symptoms of the disease appear from the point of infection to the new growth of that branch. . Free water retreats to the larger canes and is bound in the cells in the fall . . . . . . the infection travels with it. ***** (see the notes for this slide)***** Next spring, the plant will show symptoms in all new growth.

  15. Symptoms of Infection(as seen on NEW GROWTH) False Alarms • New growth • Witches’ Broom • 2,4-D damage • Yellow mosaic pattern on leaves • Distorted foliage • Herbicide Drift damage (this w/ yellowing caused by 2,4-D) • Vegetative blooms • Hyper-prickliness • Vegetative blooms • Symptomatic canes that are wider than the healthy canes from which they grew • Growth nodes will be close together

  16. Herbicide Damage (roundup)

  17. More False Alarms • ‘Normal’ funky growth • Discolored canes • Blind shoots • Rootstock suckers • Zinc deficiency • Cold damage

  18. Witches’ Broom

  19. Distorted growth

  20. Vegetative blooms

  21. Risk Increasers • Tall roses (large surface area) • Close plantings with canes touching • Nearby stands of multiflora • downwind • Lotsa roses!! • Rose gardens atop a hill • ‘Drop zones’ (spots in the yard where dead air would cause mites to drop on unlucky roses planted there)

  22. How do you treat an infected bush? • Spray bush with miticide 2. Dig up bush and garbage bag it, DON’T COMPOST 3. Carefully remove remaining roots 4. Maybe spray surrounding bushes 5. Cut off infected cane from bud union *** *** Only effective in early detection. Not recommended.

  23. Educated Guess • RRD may be an excess of growth accelerant or stimulant that forces the plant to spend energy faster than it can replenish that energy. • RRD symptoms similar to herbicide damage, specifically 2,4-D. • The herbicide 2,4-D is a synthetic auxin (plant version of a growth hormone) that kills plants by using up their energy stores faster than they can be replenished, essentially making the plant grow itself to death. The “hypothesis” I am investigating currently is whether the mode of action of RRD is similar to that of 2,4-D.

  24. Sources of Wisdom • Amrine, J. W. Jr. 22 Multiflora Rose. Division of Plant and Soil Sciences, West Virginia University, Morgantown, West Virginia, USA. <http://www.invasive.org/eastern/biocontrol/22MultifloraRose.html>. 5 November 2003. 2. Ann Peck. Rose Rosette Disease: a Web Book. <http://www.rosegeeks.com>. 20 May 2007. 3. Chuan Hong, et all. Rose Rosette Disease. Virginia Cooperative Extension. Publication Number: 450-620 <http://www.ext.vt.edu/pubs/plantdiseasefs/450-620/450-620.html>. May 2002. 4. Kevin Glaes. For information on the dormancy process in roses, meristem production, revisions, and more. Feel free to contact me with questions: James R Redington, 347 Leedy Way E., Chambersburg, PA 17202, jr3188@ship.edu

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