| Popis: |
The efficacy of low oxygen treatment depends on temperature and relative humidity. Several reports have shown that higher temperature and lower relative humidity usually decrease exposure period of low oxygen treatment for complete insect mortality. For example, at 30℃, it was reported that 3 weeks was sufficient for complete mortality of common museum insects by low oxygen treatment. However, sometimes it is considered difficult to maintain higher temperature such as 30℃,and too low relative humidity cannot be applied to museum objects.Also at 20℃,10 weeks was required for complete mortality in previous experiments. But in some cases, shorter periods are preferred for such treatments. Therefore, treatment periods of 25℃, 27.5℃ and 30℃ were studied while maintaining the relative humidity at approximately 50%RH. In the present study, rice grains containing eggs, larvae and pupae of Sitophilus zeamais, one of the most tolerant insect species for low oxygen atmosphere, were used. Low oxygen atmosphere was attained with RP-20K oxygen absorber. Temperature wasmaintained at 25℃, 27.5℃ and 30℃ respectively, and relative humidity was maintained at approximately 50%RH. After treatments, numbers of adult emergence were counted. As a result, 4-week treatment at 27.5℃ was required to achieve 100% mortality while 5-week treatment at 25℃ was required to achieve 100% mortality.These data suggest that a treatment of at least 4 weeks at 27.5℃ or 5 weeks at 25℃ are recommended to treat insect species which are tolerant to low oxygen atmosphere. |
