Methyl Bromide (MB) has been regulated by montreal protocol due to ozone depletion since 1992, and there is a need to develop MB alternative fumigation methods. To find out the efficacies and tolerance in developmental stages of citrus mealybugs (Planococcus citri) which frequently infested in imported pineapples, phosphine(PH3) gas was tested in different exposure times (2~24 hr) and concentrations (0.1∼2g/m3) in small desiccators at 8℃. Based on Lethal 99% concentration × time products (LCTP 99%) of PH3 gas to target developmental insect, 2g/m3 PH3 was applied for 24 hr in 300 m3 fumigation facility, which was designed in well sealed and evacuation system (5 air exchange/min). We monitored PH3 gas in fumigation facility to confirm CTP and checked PH3 gas in atmospheres in air ventiliation process after fumigations to make quarantine guideline and protocol for worker safety as well as efficacy to target pest.