Determination of Mortality of Life Stages of Tribolium castaneum in Rye Using Microwave Energy Paper No R. Vadivambal, D.S. Jayas, N.D.G. White Grain Storage Research Group Biosystems Engineering

Outline  Importance of disinfestation  Microwaves  Materials and Methods  Results  Conclusion

Importance of Disinfestation  Annual loss of grain due to insects is 10% in North America, 30% in Africa and Asia *  FAO estimate - 25% of food production is lost after harvesting by insects and bacteria  Post harvest losses of grains due to insects are estimated to be about 1.4 to 2.8 billion dollars per year # *Hill 1990, # USDA 2006

Properties of Microwaves  Electromagnetic waves  Frequency range: 300 MHz-300 GHz  Frequencies commonly used are 915 MHz and 2450 MHz  Travel at the speed of light, 3x10 8 m/s

Principle of Microwave Disinfestation  Based on dielectric heating effect produced in poor conductors of electricity  Possibility of selective heating in mixtures of different substances  Feasible to heat the insects at a faster rate than the grain because of difference in two dielectric constants and loss factor

Advantages of Microwave Disinfestation  No chemical residues left in the food  No environmental hazards  Insects are unlikely to develop resistance to this treatment

Objectives  To determine the mortality of life stages of Tribolium castaneum in rye using microwave energy  To determine the effect of microwave energy on germination

Materials and Methods  Rye: Musketeer  Moisture content: 14, 16, 18%  Insect: Tribolium castaneum (red flour beetle)  Life stages: Egg, larva, pupa, adult  Power (W): 200, 300, 400, 500  Exposure time (s): 28, 56  Infestation levels: 5, 10 insects / 50g

Pilot-scale Microwave Dryer Frequency: 2450 MHz Power : W Conveyor speed: 3 m/min Conveyor belt Applicator Control panel

Germination Test Germination test conducted on  14, 16 and 18% m.c. sample  200, 300, 400, 500 W  28 and 56 s

RESULTS

Mortality of T. castaneum at 14% m.c. rye Exposure time: 28 sExposure time: 56 s

Mortality of T. castaneum at 16% m.c. rye Exposure time: 28 s Exposure time: 56 s

Mortality of T. castaneum at 18% m.c. rye Exposure time: 28 sExposure time: 56 s

Results of Germination of rye Exposure time: 28 sExposure time: 56s

Conclusions  Among the life stages of T. castaneum, eggs were the most susceptible and adults were the least susceptible to microwave energy  No significant difference between the mortality of larval and pupal stage  No significant difference in the mortality of life stages at various moisture content  Germination of rye significantly decreased with increasing power level or exposure time

Acknowledgements  Canada Research Chairs Program  Natural Sciences and Engineering Research Council of Canada  Faculty of Graduate Studies  Graduate Students Association

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