Journal of Agricultural, Life and Environmental Sciences ISSN:2233-8322(Print) 2508-870X(Online)

The insecticidal effect of carbon dioxide on onion thrips, which is one of the maor pest insect of asparagus, was tested. High concentration of carbon dioxide had an insecticidal effect on the adults and larvae of onion thrips. Adult mortality was higher at 60% than at 40% CO₂ concentration. However, there was no significant larval mortality difference between two concentrations. Additionally, there was also no significant difference in treatment time required to result in adult and larval mortality at the low temperature at 60% concentration. Adult and larval mortality was increased with treatment time at the same temperature at 40% CO₂. Adult mortality reached 100% at 60% CO₂, 20°C, 24h treatment time, and at 40% CO₂, 20°C, 24h treatment time. However, some larvae were still alive when the 100% adult mortality was achieved. There was a significant difference in adult and larval mortality under the same experimental conditions. Adult mortality was higher than larval mortality under same treatment conditions at low temperature (4°C) but the opposite result occurred at high temperature (20°C, 24°C). The results showed that high carbon dioxide concentrations could cause 100% adult onion thrips mortality within 24h, but it was not suitable for complete control of larval thrips.