title: Insecticide susceptibilities in populations of two rice planthoppers, Nilaparvata lugens and Sogatella furcifera, immigrating into Japan in the period 2005-2012.
abstract: BACKGROUND
  The brown planthopper Nilaparvata lugens and the whitebacked planthopper Sogatella furcifera are both important pests on rice throughout Asia. The major cause of recent outbreaks is thought to be the development of insecticide resistance. Thus, the authors monitored insecticide susceptibilities in populations of these two insects immigrating into Japan in the period 2005-2012. Ten insecticides were tested, including members of the organophosphate, carbamate, pyrethroid, neonicotinoid and phenylpyrazole groups.
  
  
  RESULTS
  The LD50 values of N. lugens against imidacloprid increased from 2005 (0.7 µg g(-1)) to 2012 (98.5 µg g(-1)). The resistance ratio (LD50 value in 2012/baseline LD50 value in 1992) was 615.5. In contrast, LD50 values of N. lugens against fipronil were <1.0 µg g(-1) up to 2012, suggesting that N. lugens had developed no insecticide resistance to this insecticide. However, S. furcifera exhibited resistance against fipronil up to 2012. Except for the case of malathion, the resistances of N. lugens against members of the organophosphate and carbamate groups were closely similar in the period 2005-2012 to earlier determinations in 1984 and 1985.
  
  
  CONCLUSIONS
  Species-specific insecticide resistance (imidacloprid resistance in N. lugens and fipronil resistance in S. furcifera) is ongoing in populations of the two planthoppers immigrating into Japan.
authors.affiliation: NARO Kyushu Okinawa Agricultural Research Center, Koshi, Kumamoto, Japan.
authors.forename: Masaya
authors.initials: M
authors.lastname: Matsumura
authors.forename: Sachiyo
authors.initials: S
authors.lastname: Sanada-Morimura
authors.forename: Akira
authors.initials: A
authors.lastname: Otuka
authors.forename: Reiko
authors.initials: R
authors.lastname: Ohtsu
authors.forename: Shinji
authors.initials: S
authors.lastname: Sakumoto
authors.forename: Hiroaki
authors.initials: H
authors.lastname: Takeuchi
authors.forename: Masaru
authors.initials: M
authors.lastname: Satoh
mesh_terms: D000818:Animals; D002219:Carbamates / Q000633:toxicity; D005260:Female; D006430:Hemiptera; D007093:Imidazoles / Q000633:toxicity; D007305:Insecticide Resistance / Q000502:physiology*; D007306:Insecticides / Q000633:toxicity*; D058865:Introduced Species; D007564:Japan; D000073943:Neonicotinoids; D009574:Nitro Compounds / Q000633:toxicity; D063086:Organothiophosphates / Q000633:toxicity; D012275:Oryza; D011720:Pyrazoles / Q000633:toxicity; D011722:Pyrethrins / Q000633:toxicity; D013844:Thiazoles / Q000633:toxicity
chemical_list: D002219:Carbamates; D007093:Imidazoles; D007306:Insecticides; D000073943:Neonicotinoids; D009574:Nitro Compounds; D063086:Organothiophosphates; D011720:Pyrazoles; D011722:Pyrethrins; D013844:Thiazoles; C082359:imidacloprid; C082360:fipronil
keywords: brown planthopper; fipronil; imidacloprid; insecticide resistance; topical application; whitebacked planthopper