1. Future Directions in RRD Research
Mark Windham – University of Tennessee
David Byrne – Texas A&M University

2. What has been accomplished?
Tools developed/adapted to rose
Diagnostic tools – virus
Molecular
Immunological
Diagnostic tools – mite
Visual (electron microscopy)
Sampling protocol for virus (still needs work)
Sampling tools for mite
Plant tissue
Air sampling

3. What has been accomplished?
Tools developed/adapted for rose
Monitoring app on web site
Phenotyping protocol
Genotyping protocol
GBS and map for diploid
Populations for genetic studies
Diploid and tetraploid
Analytical tools – FlexQTL for diploid
Epidemiology
RRV and Mite Biology
Transmission (Tzanetakis)
Mite acquires virus in less than 5 days
Can transmit within an hour once acquired
RRV movement in plant
Systemic, how quickly move not known
Found in stems, leaves, roots, flowers and pollen
RRD movement in the field
Large field trials tracking movement
Physical barrier decrease spread
Mite biology

4. What has been accomplished?
Descriptive research
Virus sequence
Genetic variability of the virus
Identify the vector/other mites on roses
Identify mite predators associated with rose
Mite behavior on rose – feeding and transmission
Mite distribution
Within plant
Geographically
Field Control
Rogueing and Pruning
Bag and remove plants with symptoms
Pruning infected branch not effective
Garden Design
Barriers which are not host to mite can slow spread of the disease
Biological Control of the Mite
Neoseiulus, Tydeus and Amblyseius predator mites
Ongoing work
Where on plant?
Protected areas preferred
Within sepals of flower buds
Within stipules of vegetative buds
Found among glandular hairs
When move?
What environmental cues trigger movement?
Conditions for optimal reproduction and growth
Field studies in multiple locations – both sides of RRD line
Growth chamber experiments
Model to predict potential severity of RRD
Survival on roses
Ability to reproduce/survive vary with the rose

5. What has been accomplished?
Descriptive research
Miticide efficacy
Pruning and virus elimination
Garden design and mite movement
Symptomology over roses
Sources of rose rosette resistance
Genotypic map of rose
Field Control
Miticides
Weekly applications effective
Bifenthrin, fenpyroximate, spiromesifen, and spirotetramat
Optimizing spray schedule (2, 4, 6 weeks)
Testing abamectin and bifenazate
Antivirals
Under evaluation (SePRO Corp.)

6. Transmission efficiency Genotype and phenotype
Rose Rosette Disease
Rose Rosette Virus
Rose
Phyllocoptes
mite
Host reaction
Host range
Transmission efficiency
Vector specificity
Ecology and Climate
Genotype and phenotype
Feeding behavior

7. Distribution of RRD in the USA

8. Virus biology Mite biology Host plant resistance
What do we need to do?
Virus biology Mite biology Host plant resistance

9. Virus Biology

10. Virus biology? Mechanism of resistance
Virus effect on mite (Tzanetakis research)
Virus movement/distribution in plant
Virus variation in virulence
Sampling protocol for virus
Symptom development
Early detection – remote sensing
Multispectral
Raman spectrometer

11. Mite Biology

12. Mite Biology Mite rearing and development Mite monitoring
Mite epidemiology
Life cycle studies
Environmental influences
Preference/biology on resistant roses
Mite distribution on plant/in field
Survey of mite species in USA
Mite transmission

13. Breeding and Resistance

14. Breeding and Resistance
More efficient screening technique
Effect of resistant rootstock on scion
Mechanism of resistance
Inheritance of resistance
Marker development
Marker validation
Marker shared with private breeders

15. Constructing Management Strategies

18. Marketing and Economics