Rose Rosette Disease. Jim Jacobi Extension Plant Pathologist Alabama Cooperative Extension System

Transcription

1 Rose Rosette Disease Jim Jacobi Extension Plant Pathologist Alabama Cooperative Extension System

2 Rose Rosette Disease Rose Rosette Disease (RRD) is an emerging disease on roses in Alabama In 2010, RRD was found in several locations in Tennessee Valley (Huntsville + Decatur) on Knock Out Roses In 2011, RRD was found in the Birmingham area on Knock Out and other rose cultivars, but not widespread

3 Delano Park Decatur Alabama

4 Rose Rosette Disease Delano Park

5 Rose Rosette Disease Delano Park

6 Rose Rosette Disease Madison

7 Rose Rosette Disease

8 Rose Rosette Disease History Rose rosette disease (RRD) was first found in California, Wyoming, and Manitoba Canada in 1941 and has emerged as one of the most devastating diseases of roses First found on ornamental roses and Rosa woodsii, a native rose (endemic disease) RRD found in Nebraska in 1961, Kansas in 1976, Missouri in 1978, Arkansas and Oklahoma in 1978, and Kentucky and Indiana in By 1994, it was distributed as far east as Ohio, Pennsylvania, Tennessee and West Virginia

9 Distribution of RRD in 2002 Counties with RRD shown in red

10 Distribution of RRD in Alabama

11 Rose Rosette Disease Viral disease of rose that is transmitted by eriophyid mite or by grafting Common on wild multiflora rose Most rose species and cultivars are susceptible Infected rose plants often die within a few years Roses are the only plants known to be susceptible to this disease

12 Eriophyid mite Rose rosette is transmitted by the eriophyid mite (Phyllocoptes fructiphilus) The mite is yellow to brown in color and x50 microns (<1/200 inch) Eriophyid mites are 3 to 4 times smaller than an average sized spider mite The mite has four legs compared to eight legs on other mites (spider mites)

13 Eriophyid Mites Eriophyid mites can be seen with a 10 or 20x hand lens with a little practice and patience Mites are found on tender new growth on buds and between stems and leaf petioles Adult female mites overwinter on living, green tissues Most infections occur in spring (Apr June) Mites can be spread long distances on wind currents

14 Eriophyid Mites on Rose Sample

15 Eriophyid Mites on Rose Sample

16 Rose Rosette Disease Since the first report of RRD in the 40 s there has been little progress towards identification of the cause of the disease Over the years the disease was thought to be cause by a virus, a virus like agent, or most recently a phytoplasm Research published in 2011, may have solved the mystery, and indicates that the disease is caused by a virus Hopefully, this new research will lead to a fast, reliable way to detect the virus

17 Rose Rosette Disease

18 Rose Rosette Disease Symptoms of rose rosette disease are highly variable depending on cultivar Can resemble herbicide injury Common symptoms: Witches' brooms or clustering of small branches Small distorted leaf growth Leaf reddening Excessive thorn production. Unusually soft and pliable red or green thorns Thickened stems Rapid stem elongation Symptoms

19 Rose Rosette Disease Witches' Broom

20 Rose Rosette Disease Excessive thorns

21 Rose Rosette Disease Excessive thorns

22 Rose Rosette Disease Red pigmentation of new growth

23 Rose Rosette Disease New Canes Thicker Than Parent Canes

24 Rose Rosette Disease Cara Mia ornamental rose; diseased stem on left with an enlarged thorny stem; normal stem and flower on right (Photograph by Jim Amrine.)

25 Rose Rosette Disease

26 Rose Rosette Disease

27 Glyphosate Damage

28 Glyphosate Damage Glyphosate or herbicide damage can cause distorted growth. But doesn t cause: Excessive thorn production Reddened new growth Rapid stem elongation

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30 Multiflora Rose Multiflora rose was introduced to the East Coast from Japan in 1866 as rootstock for ornamental roses. Beginning in the 1930s, the U.S. Soil Conservation Service promoted it for use in erosion control and as "living fences" to confine livestock. State conservation departments also promoted multiflora rose as wildlife cover for pheasant, quail, and rabbit and as food for songbirds and encouraged its use by distributing rooted cuttings to landowners free of charge., which continued until the 1960 s Multiflora rose also has been planted in highway median strips Now considered an invasive plant in many states Infests more than 45 million acres in Eastern US RRD has been researched at Iowa State Univ. as possible biological control for multiflora rose. Herbicides and goats are other control options.

31 Multiflora Rose Leaves are pinnately compound with 5 to 11 leaflets. Leaflets are less than 1 1/2 inches long. Stipules are prominent and fringed. Flowers are white, sometimes pinkish, fragrant and 1/2 to 3/4 inch across. Fruits are bright red, 1/4 inch in diameter, and often remain on the canes until spring. The fruit provides food for wildlife during fall and winter. The seeds are readily spread long distances following ingestion by birds and animals. A single vigorous plant can produce up to a half million seeds annually.

32 Multiflora Rose James H. Miller, USDA Forest Service, Bugwood.org

33 Multiflora Rose Chris Evans, River to River CWMA, Bugwood.org James H. Miller, USDA Forest Service, Bugwood.org

34 Multiflora Rose James H. Miller, USDA Forest Service, Bugwood.org Two features that help distinguish multiflora rose from other rose species. Flowers that appear in branched clusters Fringed base of the compound leaf

35 Multiflora Rose Nancy Fraley, USDI National Park Service, Bugwood.org

36 Multiflora Rose Nancy Fraley, USDI National Park Service, Bugwood.org

37 Distribution of Nonnative Roses

38 Rose Rosette Disease and Multiflora Rose Rose Rosette Disease is fatal to multiflora rose Average lifespan after infection is 22 months Multiflora rose can be a reservoir for the disease, helping to spread the disease to cultivated roses Not seed transmitted

39 RRD on Multiflora Rose

40 RRD on Multiflora Rose Bright red RRD shoots emerging in the spring. (Photograph by Kim Amrine.)

41 RRD on Multiflora Rose RRD symptomatic inflorescence (red pannicle) on mulitflora rose, accompanied by normal flowers on healthy foliage (a separate plant) (Photograph by Jim Amrine.)

42 Rose Rosette Disease No cure for roses with rose rosette Symptomatic plants must be dug and removed, including roots Remove nearby multiflora rose, if practical Space plants so that canes and leaves do not touch each other Control Options

43 Rose Rosette Disease Prune out entire infected stem when symptoms first noticed may save plant (50:50) May stop virus spread before it moves systemically through plant If more than one stem shows symptoms, remove plant Sterilize pruning tools, although mechanical transmission in controlled experiments has been low. Control Options

44 Rose Rosette Disease Control Options Virus can survive in living root tissue Remove roots to prevent root suckers from serving as reservoir for disease

45 Rose Rosette Disease Controlling mites may help to reduce spread of RRD Products for control of eriophyid mites include: abemectin (Avid), bifenthrin (Talstar), carbaryl (Sevin), and horticultural oils Sevin is effective against eriophyid mites, but may increase spider mite problems. No mite control with imidacloprid products (Merit and Bayer Tree and Shrub Insect Control) Spraying every two weeks from April Oct isn t practical in most cases Control Options

46 Questions?