Abstract: This study shows that there is an increase in oxygen consumption of the adults of Tyrophagus putrescentiov (Schrank) when the concentration of ambient carbon dioxide rises from 0% to 8% and to 16%. But further increase in the carbon dioxide concentration up to 32% and 64% causes the decrease of the oxygen consumption of the tested mites. In mixed fumigation with 0%, 8%, 16%, 32%,64% CO2 and 0.5mg/1 PH3, the uptake of phosphine is 1.11±0.92, 1.19±0.56,5.14±1.13, 1.60±1.80, 8.08±0.85μg/hr·g respectively. The uptake of phosphine was found to increase with increase of phosphine concentration at the same concentration of carbon dioxide. However, the uptake did not increase markedly when the concentration of phosphine (0.05mg/1, 0.45mg/1) was multiplied. The results of in vitro and in vivo experiments led to the conclusions that phosphine inhibits the activity of cytochrome C oxidase and catalase, but a lower inhibitory effect on cytochrome C oxidase can be detected in in vivo experiments and theinhibition can be kept I week after exposure to the fumigant. The catalase was inhibited markedly in tested mites poisoned with phosphine and the inhibition was kept 2 weeks after exposure to the fumigant. In addition, the mode of action of phosphine and the role of CO, are discussed.

Key words: Tyrophagus putrescentiae (Schrank), phosphine, cytochrome C oxidase, catalase, oxygen consumption