Combating Rose Rosette Disease: Progress and Challenges David Byrne Basye Chair in Rose Genetics Texas A&M Universty

Combating Rose Rosette Disease: Progress and Challenges David Byrne Basye Chair in Rose Genetics Texas A&M Universty Kevin Ong, Texas AgriLife Extension Jen Olson, Oklahoma State University Mark Windham, University of Tennessee

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Rose Research on Disease Resistance USDA National Institute of Food and Agriculture (NIFA) Specialty Crop Research Initiative project, Combating Rose Rosette Disease: Short Term and Long Term Approaches (2014-51181-22644/SCRI)

Industry Collaborators Trade Organizations Nurseries Horticultural Organizations Rose Breeders Landscape Firms Pest Control Firms

Collaborators Breeders Monitoring Network SCRI RRD Grant

Combating Rose Rosette Disease: SCRI RRD Grant Components of the grant Diagnostics Best Management Practices RRD Monitoring Breeding for resistance Cultural and chemical management Economic Analysis Information Pipeline

1941 - Rose Rosette Reported in California Wyoming Manitoba, Canada Reported on Wild Rosa woodsii Cultivated roses

What does it look like? Common symptom: witches broom growth Red color Strapped leaves Increased thorniness

Shoot Proliferation Witches Broom Strapped Leaves

Rosette or Witches Broom Leaf Distortion

Excessive Thorniness Dark Red Shoots

Three Players in Disease Epidemic Pathogen: Virus Vector: Mite Reservoir: Wild rose Rose Rosette Virus Phyllocoptes fructiphilus Rosa multiflora

Emaravirus RNA strands 2011 4 strands 2015 7 strands Systemic not uniform Leaves Stems Roots Flowers Latent 4 to 20 months Diagnostics Lab test 30 minutes Field test in development Consistent if tissue shows symptoms

Eriophyid mite Very small Protected areas Float in wind Virus transmission 5 days to take up 1 hour to transmit Photo courtesy of Baldo Villegas Eriophyid mites on surface of leaf sheath as well as base.

How does the disease move? Infected Rose Clothing Hitch a & Suckers Mites Ride Tools Float in air Walk on plant Plant debris Healthy Rose Clothing Infected plants Grafting

Ways the disease does NOT move. Infected Rose Through Pruning Tools Soil Healthy Rose Pruning Tools

Distribution of Rosa multiflora Noxious weed in more than 10 states WA OR ID NV UT CA AZ AK MT WY CO NM ND MN WI SD IA NE IL KS MO OK AR MS TX LA HI ME VT MI NH NY MA CT OH PA IN MD NJ WV DE KY VA TN NC AL SC GA FL Southern distribution limited by seed cold stratification need. http://www.invasiveplantatlas.org/subject.html?sub=3071

RRD Moved from West to East OR WA CA 1953 NV ID UT AZ MT WY NM ND SD 1959 NE TX MN IA LA WI IL MS VT MI NH NY MA T OH PA IN MD NJ WV DE KY VA KS 1978 MO 1986 1996 1985 OK TN 1985 NC AR 1982 AL GA ME AK FL HI Large Reservoir of Virus in Extensive Populations of Rosa multiflora

*This is an approximate area. This map will continually be updated at RoseRosette.org

Combating Rose Rosette Disease: SCRI RRD Grant RRD monitoring network Citizen scientist approach Report location and spread of the disease Report rose on which found

Kevin Ong Texas AgriLife Extension

If you suspect RRD, submit a report RoseRosette.org Works from desktop computer, tablet or phone

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Reports are reviewed by a plant pathologist. 1 What happens after the report is submitted? They may request more information or ask you to submit a sample. 2 You ll receive a follow up report if RRD is detected. 3 You ll become part of getting closer to a solution. 4

Recent reports on Rose Rosette Disease in the USA https://roserosette.org/distribution-map/

Combating Rose Rosette Disease: SCRI RRD Grant Breeding for resistance Optimal solution Make rose a non host Long term approach

Is there Resistance to Rose Rosette Disease?

Carolinae Sources of Resistance: Rosa palustris (2x) Rosa carolina (4x) Synstylae Rosa setigera (2x) Cinnamomeae Rosa californica (2x) Pimpinellifoliae Rosa spinosissima (4x) Wild Rose Species Bractaceae Rosa bracteata (2x) Amrine, 1993; Epstein and Hill, 1999; Thomas and Scott, 1953

Hybrids with Rosa setigera Size Once Blooming Fertility Delayed Germination Lack ornamental traits

Is there resistance among commercial cultivars?

Rose accessions Susceptible No symptoms Cultivars No symptoms species 900 835 50 15 93% 5.5% 1.5% Data from Oklahoma (Jen Olson), Tennessee (Mark Windham, Alan Windham), Texas (Kevin Ong, Claude Graves, Laura Miller, Joe Plunkett ), Arkansas (Ioannis Tzanetakis), Delaware (Tom Evans) and others

Tennessee (2015) Delaware (2015) Oklahoma (2017) North Texas (2017)

Rose Rosette Research Plots Three year trials Tennessee Mark Windham Delaware Tom Evans Photos courtesy of Mark Windham, University of Tennessee and Tom Evans, University of Delaware

RRD Augmentation Photos courtesy of Mark Windham, University of Tennessee and Tom Evans, University of Delaware

RRD Augmentation RRD symptoms after 3 months on very susceptible rose Photos courtesy of Tom Evans, University of Delaware Latent period up to 2 years!

Resistance does exist but needs confirmation Species Cultivated roses 93% clearly susceptible

Time Needed Commercial Trial Endpoint Generation Cultivated Generation Resistant species First 7 Conversion First Second 11 Second 15 Third 15 Third 19 11 Fourth 19 Fourth 23 Two year greenhouse phase: produce, germinate, select seedlings Two year seedling adaptation evaluation in field Three year multiple site commercial evaluation

How Do We Make it Quicker? DNA informed breeding Marker assisted breeding

DNA-informed breeding What do we need? Plentiful molecular markers Consensus map with these markers

Genotyping by Sequencing SNP markers

LGs LG1 LG2 LG3 Marker statistics J14-3 x LC J14-3 x VS OB x RF ICD Total 189 161 103 348 Bin marker no. 38 39 48 93 Total 271 297 369 753 Bin marker no. 60 81 76 161 Total 196 123 84 340 Bin marker no. 49 43 31 91 LG4 Total 199 224 221 520 Bin marker no. 40 49 61 120 LG5 Total 275 226 303 564 Bin marker no. 50 56 64 121 LG6 Total 220 140 225 472 Bin marker no. 45 39 61 109 LG7 Total 231 263 246 530 Bin marker no. 54 62 45 125 Total 1581 1434 1551 3527 Overall Bin marker no. 336 369 386 820 * In the order of J14-3xLC : J14-3xVS : OBxRF

Phenotyping Measure the strength of resistance a rose has to the disease organism Genotyping Genotyping by sequencing approach to produce thousands of tags of genetics tags/markers on rose chromosomes Markers for black spot and RRD resistance QTL Analysis Phenotype and marker data are combined in a database for identification of quantitative trait loci using Pedimap and FlexQTL software

Accelerate Breeding Progress MAB (Marker Assisted Breeding) Reduce breeding cycle time by 50% Eliminate field screening All initial RRD resistance screening done in greenhouse Reduce seedlings that need to go to field Improve parental selection Knowledge of resistance genes

Combating Rose Rosette Disease: SCRI RRD Grant Cultural and Chemical management Minimize Amount of virus in your garden Movement of the virus Movement of infected plants Movement of the mite

Rose Rosette Disease Rose Rosette Virus Rose Environment Rose/mite interaction Phyllocoptes mite

RRD most common Midwest Eastern Northern and southern limits Recent reports of RRD on roses RoseRosette.org

Reputable nursery Many outside RRD area National Clean Plant Network Virus tested plants Check plants for symptoms RoseRosette.org

Scout the area for RRD Common sources of RRD Wild roses Multiflora rose on a roadside, infected with RRD. Unmanaged landscape plantings Early RRD symptom in landscape planting of roses.

Can you just prune off infected shoot? Not recommended Virus systemic Moves from shoots to roots to shoots Mites with virus likely on other shoots Less than 30% effective The arrow indicates a pruning cut and new shoot with RRD.

Remove symptomatic plants Large trash bags or rolls of plastic sheeting Mite movement Remove root ball No suckers Miticide applications A section of this rose is symptomatic for RRD.

Remove plants as soon as RRD is confirmed. Waiting allows mites to spread disease to more healthy plants. Removal prevents plants and landscapes from becoming victims of this disease.

It is possible if Remove entire plant plus root ball Return to verify there are no suckers Discard all debris Application of a miticide The roses in the background (left) are symptomatic for RRD while those in the foreground (right) are healthy.

Roses are often pruned in late winter-early spring Remove old blooms Primary mite overwintering location The arrows indicate last season s blooms that remain on the plant.

Discard debris in the trash or off-site Mites survival A few days without a host Much longer on rose debris Clippings should be removed Rose clippings were left on the ground.

Deadhead roses throughout the season Discard debris in the trash Left, the roses have many spent, old blooms. Right, magnified image of eriophyid mites.

Mark Windham University of Tennessee Initial trials (American Rose Society supported) Two-year trials Weekly application at highest rate Several chemicals gave complete control! Current research Additional products Optimal application schedules Mite monitoring to determine start and end Frequency trials

Commercial sites Initial trials Trade Name Active Ingredient IRAC group Akari Fenpyroximate 21A Kontos Spirotetramat 23 Forbid Spiromesifen 23 Talstar Bifenthrin 3 Other products included in the trial were Carbaryl (Sevin), Horticultural oil and Avid+Horticultural oil.

Residential landscapes Initial trials Trade Name Active Ingredient IRAC group Horticultural oils Various oils Not classified Bifenthrin Bifenthrin 3 Horticultural oil may not be effective in high pressure sites, but in areas with lesser pressure, may provide suitable control. Bifenthrin formulations are available for home garden use and are being recommended.

Do not use leaf blowers around roses during the growing season The eriophid mite in the image above is known to transmit rose rosette virus.

Leaf blowers spread the mites!

After working in garden with RRD Do not visit healthy roses that day Mite can hitch hike on clothing, gloves, and equipment Visit plantings with RRD problems late in the day The circled area indicates early RRD symptoms on this rose.

Use proper spacing Do not overcrowd roses Mites move from leaf to leaf and plant to plant High density plantings May need regular treatments with miticides

Interrupt dispersal of mites Barrier plants Structures Fences Windward side

Incorporate non - Rosa spp. to create mixed plantings Interrupt the disease cycle Landscape planting with mixed plant material including roses.

Rose Rosette Disease RRD known since the 1940s 1990s RRD epidemic in midwest to east coast 2011 RRV identified Improved diagnostics quicker, easier Systemic but not uniform Infection can be latent for 20 months Vectored Eriophyid mite, walks and floats in air Grafting

Best Management Practices Ongoing research RRD Monitoring Network Development of resistant roses Best Management Practices Start with clean plants! Rogueing and bagging infected plants Remove debris from garden, no leaf blowers Avoid going from infected to clean garden Plantings to interfere with mite movement Miticides need to optimize

WEBINAR: Managing Rose Rosette Disease in the Landscape Date: Monday, February 26, 2018 Time: 1:00 PM EST You will learn: How to identify and confirm RRD Best Management Practices for preventing RRD Treatment recommendations tailored for the landscape industry Please register at: https://attendee.gotowebinar.com/register/1623333649311193603

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