title: [Molluscicidal effect of LDS in mountainous areas of Yunnan Province].
abstract: OBJECTIVE
  To observe the molluscicidal effect of a novel molluscicide, salt of quinoid-2', 5-dichloro-4'-nitrosalicylanilide (LDS) on Oncomelania hupensis in laboratory and field of mountainous areas of Yunnan Province.
  
  
  METHODS
  With the immersion method, 10% LDS with concentrations of 0.1, 0.2, 0.4, 0.6, 0.8 mg/L was tested, and 50% niclosamide (WPN) with the concentration of 2 mg/L as well as fresh water were tested as the controls. The molluscicidal effects of 24, 48, 72 h were observed in lab and the field. With the insufflation method and powdering method, 10% LDS with doses of 0.2, 0.4, 0.6, 0.8, 1.0 g/m2 was tested and 50% WPN with the dose of 2 g/m2 as well as fresh water were tested as the controls. The molluscicidal effects of 1, 3, 7 d were observed in lab and the field.
  
  
  RESULTS
  At the room temperature of 25-26 degrees C and water temperature of 21-22 degrees C, when exposed for 72 h by the immersion method, the snail death rates of above-mentioned five concentrations of LDS and WPN as well as fresh water were 93.33%, 100%, 100%, 100%, 100%, 100% and 6.67%, respectively in lab. At the field temperature of 18-28 degrees C and water temperature of 18-23 degrees C, when exposed for 72 h by the immersion method, the snail death rates of above-mentioned five concentrations of LDS and WPN as well as fresh water were 91.11%,100%,100%, 100%, 100%, 100% and 3.33%, respectively in the field. When exposed for 7 d by the insufflation method, the snail death rates of five above-mentioned dosages of LDS and WPN as well as fresh water were 90.00%, 94.00%, 96.00% 99.00%, 99.00%, 94.00% and 6.00%, respectively in lab and 80.00%, 82.14%, 88.35%, 90.83%, 96.55%, 92.56% and 4.55%, respectively in the field. When exposed for 7 d by the powdering method, the snail death rates were 74.77%, 88.89%, 94.50%, 90.38%, 92.17%, 90.38% and 4.55%, respectively in the field.
  
  
  CONCLUSIONS
  LDS has a good molluscicidal effect on Oncomelania hupensis in mountainous areas.
authors.affiliation: Anti-schistosomiasis Station of Heqing County, Yunnan Province, Heqing 671500, China.
authors.forename: Bing-Gui
authors.initials: BG
authors.lastname: Li
authors.forename: Wen-Bao
authors.initials: WB
authors.lastname: Li
authors.forename: Yi
authors.initials: Y
authors.lastname: Dong
authors.forename: Meng-Tao
authors.initials: MT
authors.lastname: Xiong
authors.forename: Xi-Guang
authors.initials: XG
authors.lastname: Feng
authors.forename: Liang-Xian
authors.initials: LX
authors.lastname: Mu
authors.forename: Shu-Hui
authors.initials: SH
authors.lastname: Tian
authors.forename: Ping
authors.initials: P
authors.lastname: Li
authors.forename: Kang
authors.initials: K
authors.lastname: Xiong
authors.forename: Xing-Qi
authors.initials: XQ
authors.lastname: Dong
mesh_terms: D000818:Animals; D002681:China; D004305:Dose-Response Relationship, Drug; D008975:Molluscacides / Q000633:toxicity*; D009534:Niclosamide / Q000633:toxicity*; D010571:Pest Control; D012424:Rural Population; D012908:Snails / Q000187:drug effects* / Q000254:growth & development
chemical_list: D008975:Molluscacides; D009534:Niclosamide