Applied methods of chlorine dioxide gas for safe management during grain storage

다국어 초록 (Multilingual Abstract)

Increasing international trade in agricultural products has caused the influx of exotic insect pests. In the United States, damage caused by exotic insect pests is reported to reach $17 billion per year. This study tested the efficacy of chlorine dioxide (ClO2) gas to reduce the damage incurred by pests and increase the storage of grain. ClO2 is a 2.5-fold stronger oxidant than chlorine and can be used over a wide pH range. As an antimicrobial agent recognized for its disinfectant properties, ClO2 has been used since the 1950s for drinking water purification. More recently, the oxidant has been used for post-harvest control of bacteria and fungi on fruit and vegetables because of its sterilization effectiveness. Under laboratory conditions using gaseous ClO2, the mortality rate of four pests, including Sitophilus zeamais, Callosobruchus chinensis, Tribolium castaneum, and Trogoderma granarium, was confirmed. Treatment with 100 ppm ClO2 caused high mortality of S. zeamais, C. chinensis, and T. granarium, while T. castaneum showed high mortality at 200 ppm. The order of sensitivity toward ClO2 gas was C. chinensis > T. granarium > S. zeamais > T. castaneum. These results showed that ClO2 gas provided effective control of S. zeamais, T. granarium, and C. chinensis. A subsequent field experiment was perforned. One ton of grain was treated with ClO2 gas to examine the insecticidal effect against Plodia interpunctella adult, and larvae, and S. zeamais. The mortality of P. interpunctella was 100 %, but the mortality P. interpunctella larvae was low. Results for S. zeamais varied depending on its location within the grain. The mortality rates were 85% and 80% at the top, and 30% in the middle. Residual ClO2 was initially detected at the top of the grain, but none was detected at 7 days after treatment. This experiment affirmed that ClO2 is effective for stored grain pest control and can be used in the field. Moreover, there was little damage to the grain. With further experiments on the pest sensitivity and grain penetration rate of ClO2, it is expected that ClO2 could be a new alternative to toxic agents, like methyl bromide or phosphine, for stored grain pest control and safe storage of grain.

목차 (Table of Contents)

• Abstract I
• Table of Contents III
• List of Tables VI
• List of Figures VIII
• Chapter 1.
• Literature review 1
• Chapter 2.
• Response of storage insect species to ClO2 fumigation conditions 28
• 1. Abstract 29
• 2. Introduction 30
• 3. Materials and Methods
• 3.1. Preparation of insects and chlorine dioxide treatment 32
• 3.2. Statistical analysis 33
• 4. Results
• 4.1. ClO2 gas treatment sensitivity of different insect species 34
• 4.2. Effect of gaseous ClO2 on Sitophilus zeamais 36
• 4.3. Effect of gaseous ClO2 on Trogoderma granarium 38
• 4.4. Effect of gaseous ClO2 on Callosobruchus chinensis 40
• 4.5. Effect of gaseous ClO2 on Tribolium castaneum 42
• 5. Discussion 44
• 6. Reference 46
• Chapter 3.
• Chlorine dioxide fumigation to control stored product insects in rice stored in a room 50
• 1. Abstract 51
• 2. Introduction 52
• 3. Materials and Methods
• 3.1. Preparation of insects 55
• 3.2. ClO2 treatments and storage conditions 56
• 3.3. Mortality percentage of the insects 58
• 3.4. ClO2 residue analysis 59
• 3.5. Statistical analysis 60
• 4. Results
• 4.1. Mortality rate of the fifth instar larval stage of Plodia interpunctella 62
• 4.2. Mortality of Plodia interpunctella adults 64
• 4.3. Mortality of Sitophilus zeamais 66
• 4.4. Residues of ClO2 gas treatment on rice 68
• 5. Discussion 71
• 6. Reference 74
• Conclusion 80
• Abstract in Korea (국문 요약문) 82