氟虫腈对水稻害虫的作用特点及应用

通过室内生物测定和田间试验，明确了氟虫腈（商品名为锐劲特Regent）对三化暝的内吸杀虫活性、杀卵活性、持效期和对褐飞虱的杀虫活性以及对水稻主要害虫的田间防治效果，同时评价了其对天敌的安全性。结果表明：（1）氟虫腈由水稻根和茎叶内吸传导对三化暝的杀虫活性高，根和茎叶的内吸对初孵蚁暝的LC50值分别为29．12和13．07mg/L；（2）持效期长，50mg/L氟虫腈药后10d和15d对接三化暝初孵蚁暝的防效仍达92．1％和87．2％，而甲胺磷1000mg/L药后3d的防效即降为0；（3）对三化暝的杀卵效果较差，100mg/L的杀卵效果仅为30．3％，极显著低于500mg/L三唑磷的杀卵效果（95．26％）；（4）对褐飞虱的综合活性高，对3龄若虫的LC50值为10．52mg/L；（5）在江苏高淳、丹阳等地的田间试验表明，5％氟虫腈悬浮剂0．3、0．45、0．75L/hm^2可分别有效控制白背飞虱、三化暝枯心、稻纵卷叶暝、三化暝白穗和褐飞虱；（6）氟虫腈对以狼蛛为代表的稻田蜘蛛杀伤力大，但对暝卵内赤眼蜂幼期较安全。

LABORATORY TESTS AND FIELD TRAILS OF FTPRONIL AGAINST RICE INSECT PESTS

Laboratory bioassay and field experiments were conducted to evaluate the efficacy of fipronil against rice insect pests and the safety to natural enemies. Fipronil showed excellent systemic toxicity to Scirpophaga incertidas in stem and root of rice plants, with LC₅₀ of 29.12 and 13.07 mg/L, respectively. Residual efficacy of fipronil at 50 mg/L on Scirpophaga incertidas, 10 and 15 days after treatment, was 93.2% and 87.3%, respectively. While residual efficacy of methamidophos at 1000mg/L dropped to zero 3 days after treatment. It was demonstrated that fipronil had high integrated efficacy on Nilaparvata lugens with LC₅₀ of 10. 07mg/L. Fipronil at 100mg/L only killed 30.2% of eggs of Scirpophaga incertulas while triazophos at 500mg/L killed even 95.7% of the eggs. Plot experiments conducted in paddy field showed that fipronil(5% SC) at 0.45 and 0.75 L/hm² could protect rice plants from dead heart and white head endangered by Scirpophaga incertidas, respectively. And fipronil(5% SC) at 0.30 and 0.75L/hm² could effectively control Sogatella furcifera, Cnaphalocrocis medinalis and Nilaparvata lugens, respectively. Field experiments showed that fipronil was safe to Trichogramma japonicum parasitized in YSB eggs, but it was highly toxic to spiders in paddy field.