The two spotted mite, Tetranychus urticae Koch, is a global pest, and has developed severe resistance to several types of acaricides. This study compared the development in susceptible (S) and acequinocyl, bifenazate, pyridaben, abamectin and etoxazole-resistant (AcR, BR, PR, AbR and ER) strains of T. urticae by X-ray irradiation. When eggs were irradiated with 100 Gy, the egg hatching was completely inhibited in all strains. When nymphs were irradiated with 200 Gy, their hatching was completely inhibited in all strains. When adults were irradiated, the fecundity and egg hatching was decreased at 150 Gy and above, and hatchability of F1 generation was completely inhibited at 300 Gy in all strains. Adult longevity was slightly increase at 150 Gy and above. In addition, we performed quantitative real-time PCR on several genes. To examine the difference of all strains on radiation stress-induced gene expression, we performed quantitative RT-PCR (qPCR) of several known stress-induced genes.

• Won Jin Kang(Department of Plant Medicine, Chungbuk National University)
• Seung-Hwan Yun(Department of Plant Medicine, Chungbuk National University)
• Hyun Kyung Kim(Department of Plant Medicine, Chungbuk National University)
• Hyun-Na Koo(Department of Plant Medicine, Chungbuk National University)
• Gil-Hah Kim(Department of Plant Medicine, Chungbuk National University)