Fumigation Activity against Phosphine-Resistant Tribolium castaneum (Coleoptera: Tenebrionidae) Using Carbonyl Sulfide

Phosphine resistance is occurring among stored-grain pests worldwide. This study investigated the fumigation activity of phosphine (PH ) and carbonyl sulfide (COS) against domestic strain (d-strain) , resistance strain (r-strain) . and . All developmental stages of the pests were exposed to two fumigants (PH and COS), and the fumigation activity according to the dose and exposure time was evaluated in a 12-L desiccator and 0.5 m fumigation chamber. The rice sorption rate and quality following exposure to thetwofumigants were evaluated. The mortality was 2.9% in r-strain . , 49.5% in d-strain . and 99.2% in . when 2 mg/L PH was used in a 12-L desiccator for 4 h. However, all pest developmental stages showed 100% mortality after 24 h of exposure in the 0.5 m fumigation chamber, except for the r-strain . . A mortalityof 100% was observed in all of the r-strain . developmental stages at an exposure time of 192 h. For COS applied at 40.23 mg/L and 50 g/m in the 12-L desiccator and the 0.5 m fumigation chamber, respectively, 100% mortality was observed across all developmental stages regardless of species and strain. The sorption of COS was 10% higher than that of PH , but there was no significant difference in rice quality compared to that in the control. Therefore, this study suggests that COS can be used for controlling . resistant to PH .