volume | PIER Journals

Abstract

Radio frequency (RF) dielectric heating was tested to control Cryptolestes ferrungineus S. in the bulk wheat samples (ca.152 g, dia. = 50 mm, ht.= 100 mm) at the MCs (%, w. b.) of 12, 15, and 18 using a pilotscale RF heater (1.5 kW, 27.12MHz) in the batch mode. When the temperature of the hottest spot (geometric center) of the sample, TH was at 80°C, all the adult insects were found dead at the cold spots, near bottom-wall, at 50.7°C to 56.0°C depending up on the wheat MCs. The temperatures of the insect-slurries higher than that of the bulk wheat by 0.8°C to 15.1°C indicated the selective heating of the insects. The mortalities of adult insects were almost constant within the quarantine period, QP1 (5 wk). The elapsed time during QP1 had a significant effect only on the insects' mortalities with the wheat at 12% MC. The wheat MC had only marginal significance on the absolute mortalities of insects. The larvae were completely destroyed at temperatures between 55°C and 60°C. The complete mortality of all life stages (eggs, larvae, pupae, and adults) of the insect was achieved at T_H = 80°C without any emergence of the insects during QP2 (8 wk). The RF treatment enhanced the germination of the wheat kernels at 12% MC while it was decreased by 2% to 33% depending up on the wheat MC, and the treatment temperature. Temperature had no significant effect on the falling numbers, and the yields of flour, bran, and shorts, and the peak-bandwidth and the MC of the wheat, and the flour protein values. The means of the mixing-development-time deferred from the controls mostly for the wheat at 15% MC and T_H = 70°C, and 18% MC and T_H = 70°C and 80°C. The mean-peak-height and the color values varied between 4% and 16%, and 3% and 6% off the controls depending up on the temperatures. The uniform temperature of 60°C should be enough to control all life stages of the insect completely with a little or no changes in the important product quaities and germination of the wheat at MCs safe for the storage. Future research mainly focused on better estimation of the insect-to-grain electric field intensities is essential.

1. Wang, S., G. Tiwari, S. Jiao, J. A. Johnson, and J. Tang, "Developing postharvest disinfestation treatments for legumes using radio frequency energy," Biosyst. Eng., Vol. 105, 342-349, 2010. Google Scholar

2. Ponomaryova, I., A. Torrecillas, N. Herrera, A. Velazquez, et al. "Insect control by radio-frequency high-strength electric fields," 2009 6th International Conference on Electrical Engineering, Computing Science and Automatic Control, CCE 2009, 1-5, Toluca, Nov. 10-13, 2009. Google Scholar

3. Vadivambal, R., D. S. Jayas, and N. D. G. White, "Determination of mortality of di®erent life stages of Tribolium castaneum (Coleoptera: Tenebrionidae) in stored barley using microwaves," Journal of Economic Entomology, Vol. 101, No. 3, 1011-1021, 2008. Google Scholar

4. Vadivambal, R., D. S. Jayas, and N. D. G. White, "Wheat disinfestation using microwave energy," Journal of Stored Products Research, Vol. 43, 518-514, 2007. Google Scholar

5. Wang, S., J. Tang, T. Sun, E. J. Mitcham, T. Koral, and S. L. Birla, "Considerations in design of commercial radio frequency treatments for postharvest pest control in in-shell walnuts," Journal of Food Engineering, Vol. 77, 304-312, 2006. Google Scholar

6. Soproni, V. D., F. I. Hathazi, M. N. Arion, C. O. Molnar, and L. Bandici, "Aspects regarding the adapting and optimization of mixed drying systems microwave-hot air for the processing of agricultural seeds," PIERS Proceedings, 210-213, Beijing, China, Mar. 23-27, 2009. Google Scholar

7. Shrestha, B. and O. D. Baik, "Radio frequency (RF) selective heating of stored-grain insects at 27.12MHz - A feasibility study," Biosyst. Eng., Vol. 114, 195-204, 2013. Google Scholar

8. Cofie-Agbior, R., R. Muir, N. Sinha, and P. G. Fields, "Heat production by adult Cryptolestes ferrugineus (Stephens) of different ages and densities," Postbarvest Biol. Technol., Vol. 7, 371-380, 1996. Google Scholar

9. Nelson, S. O., "Dielectric spectroscopy in agriculture," J. Non-Cryst. Solids, Vol. 351, 2940-2944, 2005. Google Scholar

10. Guo, W., X. Wu, X. Zhu, and S. Wang, "Temperature-dependent dielectric properties of chestnut and chestnut weevil from 10 to 4500 MHz," Biosyst. Eng., Vol. 110, 340-347, 2011. Google Scholar

11. Ikediala, J. N., J. Tang, S. R. Drakeand, and L. G. Neven, "Dielectric properties of apple cultivars and codling moth larvae," Transactions of the American Society of Agricultural Engineers , Vol. 43, No. 5, 1175-1184, 2000. Google Scholar

12. Rashkovan, V. M., N. A. Khizhnyak, A. V. Basteev, L. A. Bazyma, L. N. de Rivera, and I. A. Ponomaryova, "Interaction of electromagnetic waves with granular product and insects," J. Microw. Power Electromagn. Energy, Vol. 36, No. 4, 225-235, 2003. Google Scholar

13. Hamid, M. A. K., C. S. Kashyap, and R. V. Cauwenberghe, "Control of grain insects by microwave power," J. Microwave Power, Vol. 3, No. 3, 126-135, 1968. Google Scholar

14. Wang, S., M. Y. G. Monzon, J. Tang, E. J. Mitcham, and J. W. Armstrong, "Temperature-dependent dielectric properties of selected subtropical and tropical fruits and associated insect pests," Transactions of the American Society of Agricultural Engineers, Vol. 48, No. 5, 1873-1881, 2005. Google Scholar

15. Wang, S., J. Tang, J. A. Johnson, J. E. Mitcham, J. D. Hansen, G. Hallman, S. R. Drake, and Y. Wang, "Dielectric properties of fruits and insect pests as related to radio frequency and microwave treatments," Biosyst. Eng., Vol. 85, No. 2, 201-212, 2003. Google Scholar

16. Nelson, S. O., P. G. Bartley, Jr., and K. C. Lawrence, "RF and microwave dielectric properties of stored-grain insects and their implications for potential insect control," Transactions of the American Society of Agricultural Engineers, Vol. 41, No. 3, 685-692, 1998. Google Scholar

17. Wang, S., J. Tang, R. P. Cavalieri, and D. C. Davis, "Differential heating of insects in dried nuts and fruits associated with radio frequency and microwave treatments," Transactions of the American Society of Agricultural Engineers, Vol. 46, No. 4, 1175-1182, 2003. Google Scholar

18. Wang, S., M. Monzon, J. A. Johnson, E. J. Mitcham, and J. Tang, "Industrial-scale radio frequency treatments for insect control in walnuts: II. Insect mortality and product quality," Postharvest Biol. Technol., Vol. 45, No. 2, 247-253, 2007. Google Scholar

19. Johnson, J. A., K. A. Valero, S. Wang, and J. Tang, "Thermal death kinetics of red flour beetle (Coleoptera: Tenebrionidae)," J. Econ. Entomol., Vol. 97, No. 6, 1868-1873, 2004. Google Scholar

20. Armstrong, J. W., J. Tang, and S. Wang, "Thermal death kinetics of mediterranean, malaysian, melon, and oriental fruit fly (Diptera: tephritidae) eggs and third instars," J. Econ. Entomol., Vol. 102, No. 2, 522-532, 2009. Google Scholar

21. Abbott, W. S., "A method of computing the effectiveness of an insecticide," J. Am. Mosq. Control. Assoc., Vol. 3, No. 2, 302-303, 1925. Google Scholar

22. Fields, P. G., "The control of stored-product insects and mites with extreme temperatures," Journal of Stored Products Research, Vol. 28, 89-118, 1992. Google Scholar

23. Nelson, S. O., "Review and assessment of radio-frequency and microwave energy for stored-grain insects control," Transactions of the American Society of Agricultural Engineers, Vol. 39, 1475-1485, 1996. Google Scholar

24. Nelson, S. O., "Use of microwave and lower frequency RF energy for improving alfalfa seed germination," Journal of Microwave Power, Vol. 11, No. 3, 271-277, 1976. Google Scholar

25. Nelson, S. O. and E. R. Walker, "Effect of radio frequency electrical seed treatment," Agr. Engr., Vol. 42, No. 12, 688-691, 1961. Google Scholar

Dr. Bijay Shrestha

Dr. Daeung Yu

Dr. Oon-Doo Baik