title: Species-specific insecticide resistance to imidacloprid and fipronil in the rice planthoppers Nilaparvata lugens and Sogatella furcifera in East and South-east Asia.
abstract: BACKGROUND
  In 2003 the development of insecticide resistance against neonicotinoids in the brown planthopper (BPH), Nilaparvata lugens (Stål) (Homoptera: Delphacidae), was first observed in Thailand and has since been found in other Asian countries such as Vietnam, China and Japan. However, the LD(50) values of BPH and the whitebacked planthopper (WBPH), Sogatella furcifera (Horváth), against both neonicotinoid and phenylpyrazole insecticides have been poorly reported in many Asian countries.
  
  
  RESULTS
  The topical LD(50) values for imidacloprid in the BPH populations collected from East Asia (Japan, China, Taiwan) and Vietnam in 2006 were 4.3-24.2 microg g(-1) and were significantly higher than those collected from the Philippines (0.18-0.35 microg g(-1)). The BPH populations indicated a positive cross-resistance between imidacloprid and thiamethoxam. Almost all the WBPH populations from Japan, Taiwan, China, Vietnam and the Philippines had extremely large LD(50) values (19.7-239 microg g(-1) or more) for fipronil, except for several populations from the Philippines and China.
  
  
  CONCLUSIONS
  Species-specific changes in insecticide susceptibility were found in Asian rice planthoppers (i.e. BPH for imidacloprid and WBPH for fipronil). Insecticide resistance in BPH against imidacloprid occurred in East Asia and Indochina, but not in the Philippines. In contrast, insecticide resistance in WBPH against fipronil occurred widely in East and South-east Asia.
authors.affiliation: National Agricultural Research Centre for Kyushu Okinawa Region, Kumamoto, Japan. mmasa@affrc.go.jp
authors.forename: Masaya
authors.initials: M
authors.lastname: Matsumura
authors.forename: Hiroaki
authors.initials: H
authors.lastname: Takeuchi
authors.forename: Masaru
authors.initials: M
authors.lastname: Satoh
authors.forename: Sachiyo
authors.initials: S
authors.lastname: Sanada-Morimura
authors.forename: Akira
authors.initials: A
authors.lastname: Otuka
authors.forename: Tomonari
authors.initials: T
authors.lastname: Watanabe
authors.forename: Dinh
authors.initials: D
authors.lastname: Van Thanh
mesh_terms: D000818:Animals; D001210:Asia, Southeastern; D005202:Asia, Eastern; D005260:Female; D006430:Hemiptera; D007093:Imidazoles; D007305:Insecticide Resistance; D007306:Insecticides; D007928:Lethal Dose 50; D000073943:Neonicotinoids; D009574:Nitro Compounds; D011720:Pyrazoles; D013045:Species Specificity
chemical_list: D007093:Imidazoles; D007306:Insecticides; D000073943:Neonicotinoids; D009574:Nitro Compounds; D011720:Pyrazoles; C082359:imidacloprid; C082360:fipronil