1. Why clean plants?

3. Leafroll virus effects  Delayed maturity  Lower sugar content  Increased acidity  Lower color  Decreased crop level Declining wine quality.

8. Leafroll management costs 83 acre Cabernet vineyard ActivityWhoCost Scouting Hourly employees $ 1,057 $ 1,057 Sampling Vit staff time ? AnalysisWSU $ 617 $ 617 Vine Removal Hourly employees $ 588 $ 588 Replanting Hourly employees $ 157 $ 157 Watering Hourly employees $ 1,173 $ 1,173 $ 3,592 $ 3,592

9. Leafroll management costs  Costs associated with preventing spread –Insecticides –Crew movement –Extensive sanitation procedures  Loss of revenue potential

10. 1994 planting – 11 years of revenue on a 30-40 year investment!!

11. Leafroll management costs  Costs associated with preventing spread –Insecticides –Crew movement –Extensive sanitation procedures  Loss of revenue potential  Fallow period?

13. Virus Spread

19. Clean vines for new plantings  Certified material

22. Clean vines for new plantings  Certified material  Next best thing…

23. Sampling – case history  Chardonnay – “clean block” –Field observations – not possible; dormant season –Bulk sampling – 4” cane samples from standardized location on each vine.  164 random vines ~ 1% –Focus on most prevalent virus strains = 1,2,3

24. Sampling – case history  Chardonnay – “clean block” results –20 positive results by ELISA –Not a viable block for propagation  Plan ‘B’

25. Sampling – case history  Chardonnay – plan ‘B’  ID a good block and reviewed results of previous testing.  During the growing season -visual symptoms surveyed in August.  3 symptomatic vines found and tested for strains 1,2,3,5 & 7.  Bulk sample for GLRaV 3.

26. Sampling – case history  Chardonnay – plan ‘B’ results –False positive. –Bulk sampling showed no positive samples. –Use this block for propagation.

27. Deep thoughts Virus management  Start with clean material!  Scout your vineyards  Keep good records –Scouting –Testing –Planting records  Make a plan –Infected vine removal (?) –Spread prevention measures –Replanting plan$