This study investigated the fumigant activity of phosphine (PH3) on 2 kinds of mealybug (Pseudococcus longispinus and P. orchidicola (Hemiptera: Pseudococcidae)) adults and nymphs. All of the two mealybugs adults showed higher LCT99 values than nymphs, and P. longispinus showed higher tolerance than P. orchidicola in a 12 L desiccator. The absorption of phosphine on 13 nursery plants showed 12.2~41.5% difference depending on the plant. All of the mealybugs treated with phosphine 2 mg/L in 0.5 m3 fumigation chamber for 4 h showed 100% fumigant activity, except P. longispinus adult (approximately 90% at bottom part). However, when the exposure time was increased to 24 h, all of them showed 100% mortality. In the treatment of 10 m3 container, the 24 h treatment of phosphine showed 100% mortality to P. longispinus and P. orchidicola adults and nymphs. In all the experiments, no phytotoxicity of phosphine observed on 13 plants until 1 month after treatment.

• Sung Woo Cho(Department of Plant Medicine, Chungbuk National University, Korea)
• YeJin Kyung(Department of Plant Medicine, Chungbuk National University, Korea)
• Geun-Ho Park(Department of Plant Medicine, Chungbuk National University, Korea)
• Sun-Ran Cho(Department of Plant Medicine, Chungbuk National University, Korea)
• Byung-Ho Lee(Institute of Agriculture and Life Science, Gyeongsang National University)
• Jeong-Oh Yang(Plant Quarantine Technology Center, Animal and Plant Quarantine Agency)
• Hyun-Na Koo(Department of Plant Medicine, Chungbuk National University, Korea)
• Hyun Kyung Kim(Department of Plant Medicine, Chungbuk National University, Korea)
• Gil-Hah Kim(Department of Plant Medicine, Chungbuk National University, Korea)