Attagenus unicolor japonicus, the black carpet beetle is a worldwide pest that damages a variety of animal products, inlcuding stored grains, silk, and wool. I investigated the life cycle of the pest and the fumigation activities of phosphine (PH3) and carbonyl sulfide (COS) against the pest. At each developmental stage of the pest, the fumigation activity according to the dose and exposure time was evaluated in a 12 L-desiccator, 0.65 m3-, and 10 m3-fumigation chamber, respectively. After exposure to the two fumigants, the adsorption rates and quality of rice were evaluated.
A. unicolor japonicus is a holometabolous insect, and overwinters as a larva from December to February of the following year. The egg period is 9.1 days, , the larval period is 1-2 years, the pupal period is 7.3 days and the adult period is 11.3 days for females and 11.0 days for males. The female lays 88.5 eggs on average.
The fumigation effects of the PH3 and COS were investigated for each stage of A. unicolor japonicus. 100% mortality in all stages except egg stage (80.4%) was observed after 24 h of exposure to 1.0 mg/L of PH3 in 12 L-desiccator. Even with the COS treatment of 15.2 mg/L, 100% mortality was observed in all the stages except egg stage (40.0%). However, when the exposure time (48 h) and dose (2 mg/L of PH3, 40 mg/L of COS) of both fumigants were increased, 100% fumigation activity was shown in all the stages in both 0.65 m3- and 10 m3-fumigation chamber experiments.
The adsorption rates of PH3 and COS were 90% and 81%, respectively, but there was no significant difference in rice quality compared to the control. Therefore, this study presents the fundamental data on the life cycle of A. unicolor japonicus and suggests that both fumigants can be used as an alternative to MB fumigant for the control of A. unicolor japonicus.