Effect of gaseous ozone for control of stored product pests at low and high temperature

• Ozonation has potential for control of insects in grain and other stored products.
• Ozone and 3 temperatures were tested on Sitophilus granarius and Plodia interpunctella.
• All stages die after exposure to 131 ppm ozone for 8 days.
• Some insects survive treatment with to 33 ppm ozone for 6 days.
• The effect of the treatment was unaffected by temperature in the range of 8° and 30 °C.

Gaseous ozone (O3) has shown potential for control of insects in stored grain. A previous laboratory study determined doses of ozone necessary to control freely exposed and internal stages of eleven stored product pest species at 20 °C. In this study the impact of temperature on the effect of ozone was tested on two species of stored product pests: Sitophilus granarius and Plodia interpunctella. Insects were exposed to continuous flows of ozone in doses of approximately 33 ppm for 6 d or approximately 131 ppm for 8 d at low temperatures between 7.3 and 7.9 °C and high temperatures between 29.6 and 31.6 °C, respectively. Results from the previous study conducted at 20 °C were used in the data analysis.The result of the treatments was unaffected by the temperatures used in the study. Treatment with a high dose of ozone for 8 d led to full mortality in all stages of S. granarius and all stages of P. interpunctella except eggs at the high temperature. At the low dose for 6 d some survival was found in both species at all three temperatures. Thus, in the temperature range studied, we could not confirm that the effect of ozone on S. granarius and P. interpunctella is related to temperature.