1. The effect of low levels of CIPC on Seed Potato Performance John Walsh Associate Principal Scientist, Potato Storage McCain Foods Limited

2. CIPC on Seed? 2

3. CIPC on Seed 30 years ago Most growers grew some seed and had a CIPC-free storage CIPC wasn’t used as much Now Many growers have no CIPC-free storages 3

4. CIPC on Seed? 4 From one of the Canadian Labels

5. CIPC on Seed? 5 From one of the US Labels

6. CIPC on Seed? Potatoes affected by CIPC will eventually sprout, but not properly 6

7. Idaho Trial on CIPC on Seed 7 CIPC sprayed on seed potato tubers prior to planting

8. Seed potatoes in CIPC treated store No one sprays 2.5 ppm CIPC directly on seed Need conditions more similar to what would happen in industry 8

9. Trial Setup 3 Storages No CIPC: Wicklow res. storage Exposed but clean: Treated storage washed and disinfected Exposed but dirty: Treated storage with potatoes still in it, not cleaned 9

10. Trial Setup Two varieties: Russet Burbank Innovator Four exposure times 1, 2, 3, & 4 weeks 10

11. Residue Results 11

12. Residue Results Could detect low levels But treatment results were unexpected Note: couldn’t detect it in the air 12

13. Cleaned storage 13 Storage was steam cleaned and disinfected before being used to cut seed. Chipping bins were sealed off to prevent contamination

14. Residue Results Went back and re- tested results Results confirmed! 14

15. Residue Results Exposure time Relatively little effect CIPC there from the beginning 15

16. Field Results 16

17. Field Results Planted potatoes in single rows 30’ long 17 Spray Row Guard Row Innovator-CIPC-21 Innovator-CIPC-Cleaned-7 Innovator-No-CIPC-14Innovator-No-CIPC-28 Russet Burbank-CIPC-Cleaned-7 Russet Burbank-No-CIPC-21 Russet Burbank-CIPC-Cleaned-21Russet Burbank-CIPC-Cleaned-14 Russet Burbank-CIPC-21 Russet Burbank-No-CIPC-28 Innovator-CIPC-Cleaned-28 Russet Burbank-CIPC-7 Russet Burbank-No-CIPC-7 Russet Burbank-CIPC-14 Guard Row Spray Row Guard Row Innovator-CIPC-28 Innovator-CIPC-Cleaned-14 Innovator-No-CIPC-7 Innovator-No-CIPC-21 Russet Burbank-No-CIPC-14 Innovator-CIPC-7 Russet Burbank-CIPC-Cleaned-28 Russet Burbank-CIPC-28 Innovator-CIPC-14 Innovator-CIPC-Cleaned-21 Guard Row Spray Row Innovator-No-CIPC-28 Russet Burbank-CIPC-Cleaned-28 Innovator-CIPC-28 Russet Burbank-No-CIPC-28 Russet Burbank-CIPC-Cleaned-21Russet Burbank-CIPC-Cleaned-14 Innovator-CIPC-21 Russet Burbank-CIPC-28 Innovator-No-CIPC-7 Innovator-CIPC-Cleaned-7 Russet Burbank-No-CIPC-14 Russet Burbank-CIPC-Cleaned-7 Russet Burbank-CIPC-7 Innovator-CIPC-Cleaned-21 Russet Burbank-CIPC-21 Innovator-No-CIPC-14 Russet Burbank-No-CIPC-21 Russet Burbank-CIPC-14 Innovator-CIPC-14 Innovator-CIPC-7 Innovator-CIPC-Cleaned-28Innovator-CIPC-Cleaned-14 Russet Burbank-No-CIPC-7 Innovator-No-CIPC-21 Innovator-CIPC-Cleaned-28 Innovator-No-CIPC-21 Innovator-CIPC-28 Innovator-CIPC-7 Russet Burbank-CIPC-21 Russet Burbank-CIPC-Cleaned-28 Innovator-CIPC-14 Russet Burbank-CIPC-28 Innovator-CIPC-21 Innovator-CIPC-Cleaned-21 Russet Burbank-CIPC-Cleaned-7 Russet Burbank-No-CIPC-21 Russet Burbank-CIPC-Cleaned-14 Russet Burbank-CIPC-14 Russet Burbank-CIPC-7 Russet Burbank-No-CIPC-28 Innovator-No-CIPC-7 Russet Burbank-CIPC-Cleaned-21 Innovator-No-CIPC-14 Russet Burbank-No-CIPC-14 Innovator-CIPC-Cleaned-7 Innovator-CIPC-Cleaned-14 Russet Burbank-No-CIPC-7 Innovator-No-CIPC-28 Russet Burbank-No-CIPC-21 Innovator-No-CIPC-21 Russet Burbank-CIPC-Cleaned-7 Russet Burbank-CIPC-7 Russet Burbank-No-CIPC-28 Innovator-CIPC-21 Innovator-No-CIPC-28 Innovator-CIPC-Cleaned-14Innovator-CIPC-Cleaned-28 Russet Burbank-No-CIPC-14 Russet Burbank-CIPC-28 Innovator-No-CIPC-14 Innovator-CIPC-28 Innovator-CIPC-Cleaned-21 Innovator-CIPC-14 Innovator-No-CIPC-7 Russet Burbank-CIPC-Cleaned-28Russet Burbank-CIPC-Cleaned-14 Russet Burbank-No-CIPC-7 Innovator-CIPC-7 Russet Burbank-CIPC-Cleaned-21 Russet Burbank-CIPC-14Russet Burbank-CIPC-21 Innovator-CIPC-Cleaned-7

18. Field Results Emergence Was delayed by higher levels of CIPC Counted all plants in plots Note: final emergence was not significantly different 18 * * * * * *

19. Field Results Plant growth Also affected Less clear 19 * * *

20. Field Results Yield Also affected!!! 8% yield loss Statistically significant Cleaned storage from other two storages Averaged over both varieties 20 ABABAAA

21. Take-Aways 21

22. Take-Aways As little as 0.05-0.10 ppm (50-100 ppb) may have an effect on: Emergence Growth Total Yield 22

23. Take-Aways Do not use storage treated after Christmas Or a storage connected to a storage treated after Christmas 23

24. Take-Aways Clean, disinfect and air out storage before bringing in seed 24

25. Take-Aways Potatoes pick up the the residues quickly Certainly less than a week Maybe as little as a day 25

26. Take-Aways CIPC is volatile and persistent Can take many years to dissipate! 26

27. Next Year 27

28. Next Year Two-step approach: Spray seed tubers with CIPC to achieve 0 - 0.4 ppm in residues 0, 0.025, 0.050, 0.100, 0.200, 0.400 ppm And then plant them out 28

29. Next Year Two-step approach: Spray seed tubers with CIPC to achieve 0 -.4 ppm in residues Measure seed tuber levels in grower storages. 29

30. 30 Questions?