Radio Frequency Treatments as Alternative to Chemical Fumigation for Insect Control in Nuts

1. Radio Frequency Treatments as Alternative to Chemical Fumigation for Insect Control in Nuts Juming Tang S. Wang J. Hansen, J. Johnson, E. Mitcham, S. Drake, G. Hallman

2. Juming Tang; Shaojin Wang, Bio. Systems Eng., WSU, WA • James D. Hansen, USDA-ARS, Wapato, WA • Judy A. Johnson, USDA-ARS, Fresno, CA • Elizabeth Mitcham, UC Davis, CA • Stephen R. Drake, USDA-ARS, Wenatchee, WA • Guy Hallman, USDA-ARS, Weslaco, TX

3. RF Treatments as Alternative to Chemical Fumigation for Insect Control in Nuts • Introduction • Insect mortality • Fruit quality curve • Dielectric property • Heating uniformity • Differential heating • Process protocols for walnuts

4. INTRODUCTION Washington State University started working on developing effective thermal processes based on RF and microwave energy in 1996, with original focus on codling moth. We now expand to other insect pests for international and intrastate trades

5. Entomology Plant physiology Engineering In 2000, formed a consortium: entomologists, plant physiologists and engineers from two universities (WSU and UC Davis), and four USDA ARS Stations in Three States (WA, CA and TX).

6. Targeted commodities and insects Walnut Almond Cherry Apple Orange Grapefruit Codling moth Navel orangeworm Indianmeal moth Fly

7. RF and Microwave Heating: Volumetric heating -- the electromagnetic waves directly couple with material to generate heat.

8. Electromagnetic spectrum 915 MHz 2450 MHz Microwaves 27.12 MHz Quantum energy >5 eV Radio waves Infrared Ultra violet Quantum energy <0.00001 eV

9. Molecular Agitation Polarity is reversed 27 MILLION times per second (27MHz) (Courtesy of Strayfield, UK)

10. RF Treatments as Alternative to Chemical Fumigation for Insect Control in Nuts • Introduction • Insect mortality • Fruit quality curve • Dielectric property • Heating uniformity • Differential heating • Process protocols for walnuts

11. Acceptable time-temperature treatment area obtained from different mortality and quality curves Source: Tang et al., 2000. Postharvest Bio. Technol., 21, 129-145.

12. The heating block system developed at WSU

13. Schematic diagram of the heating block system developed at WSU Source: Wang et al., 2002. J. Stored Prod. Res., in press.

14. Mortality curve of fifth-instar navel orangeworm at different temperatures. N0 and N stand for initial (600) and survival insect numbers Source: Wang et al., 2002. J. Stored Prod. Res., in press.

15. TDT curve of 5th-instar Indianmeal moth (IMM), codling moth (CM) and navel orangeworm (NOW) Source: Wang et al., 2002. Postharvest Bio. Technol. in review.

16. Mortality (%) of NOW for three different life stages at a heating rate of 18°C/min (3 replicates) Source: Wang et al., 2002. Postharvest Bio. Technol. in review.

17. RF Treatments as Alternative to Chemical Fumigation for Insect Control in Nuts • Introduction • Insect mortality • Fruit quality curve • Dielectric property • Heating uniformity • Differential heating • Process protocols for walnuts

18. TDT curve of codling moths and fruit quality of PNW cherries Quality data from Steve Drake, USDA ARS Wenatchee

19. RF Treatments as Alternative to Chemical Fumigation for Insect Control in Nuts • Introduction • Insect mortality • Fruit quality curve • Dielectric property • Heating uniformity • Differential heating • Process protocols for walnuts

20. HP Dielectric Property Measurement System

21. Source: Tang et al., 2000. Postharvest Bio. Technol., 21, 129-145.

22. RF Treatments as Alternative to Chemical Fumigation for Insect Control in Nuts • Introduction • Insect mortality • Fruit quality curve • Dielectric property • Heating uniformity • Differential heating • Process protocols for walnuts

23. Walnut kernel temperature at five locations on three layers when subjected to RF (P=0.6kW) and hot air treatments ( air temp.=53°C, air speed =1 m/s) Source: Wang et al., 2001. ASAE paper No. 016170, 16p.

24. RF Treatments as Alternative to Chemical Fumigation for Insect Control in Nuts • Introduction • Insect mortality • Fruit quality curve • Dielectric property • Heating uniformity • Differential heating • Process protocols for walnuts

25. Temperature profiles of walnut kernels and codling moth slurry when subjected to 27 MHz RF system

26. RF Treatments as Alternative to Chemical Fumigation for Insect Control in Nuts • Introduction • Insect mortality • Fruit quality curve • Dielectric property • Heating uniformity • Differential heating • Process protocols for walnuts

27. Treating Infested Walnuts Using 27.12 MHz RF

28. Schematic view of the combined RF and hot air treatments of in-shell walnuts for drying and insect control Source: Wang et al., 2002. Postharvest Bio. Technol. in review.

29. Temperature of in-shell walnut kernel when subjected to RF and forced hot air treatments (air temperature, 53oC; air velocity, 1m/s) Source: Tang et al., 2000. Postharvest Bio. Technol., 21, 129-145.

30. Mortality of 5th instar codling moth in walnuts after RF treatments (year 2000) Source: Wang et al., 2001. Postharvest Bio. Technol., 22, 29-38.

31. Mortality of 5th Instar Navel Orangeworms in in-shell walnuts after RF treatments (Year 2001) Source: Wang et al., 2002. Postharvest Bio. Technol. in review.

32. Quality characteristics of in-shell walnuts treated by RF energy (53°C+5min) (year 2000) Source: Wang et al., 2001. Postharvest Bio. Technol., 22, 29-38.

33. Quality characteristics of in-shell walnuts treated by radio frequency energy with 3 replicates (Year 2001)* * Tests conducted by Diamond Walnuts, CA Source: Wang et al., 2002. Postharvest Bio. Technol. in review.

34. CONCLUSIONS • It is possible to use radio frequency heating as a short-time treatment for insect pest control. • The process completely kills insect pests without causing damage to selected commodities. • We may be ready to scale-up RF process for inshell walnut nut treatment.

35. RF HeatingFCC approved frequencies for ISM Applications:13.56 MHz (22 m), 27.12 MHz (11 m), and 40.68 MHz (7.4 m)

36. Please visit our USDA-IFAFS Website:http://www.bsyse.wsu.edu/IFAFS

37. Thanks!