Fumigation Activity against Phosphine-Resistant (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.