稻田常用杀菌剂对褐飞虱若虫的杀伤作用

 研究了8种杀菌剂5种浓度对褐飞虱2、3龄若虫的直接杀伤作用和毒力大小。杀伤试验结果表明，异稻瘟净即使在1/4倍常规推荐浓度(43.75 mL/667 m²)下，对褐飞虱2、3龄若虫杀伤作用也很明显。甲基立枯磷除1/4倍常规浓度(25 mL/667 m²)下对褐飞虱2、3龄若虫杀伤作用不明显外，在50、100、200、400 mL/667 m²的浓度下,于第3天开始均有显著的杀伤作用。4倍常规推荐浓度的叶枯灵(600 g/667 m²)、井岗霉素(500 mL/667 m²)、三环唑(400 g/667 m²)、叶青双(400 g/667 m²)对褐飞虱的2、3龄若虫的杀伤在第1天很小，在第3、5、7天与对照差异显著，其它各浓度均无明显杀伤作用，但百菌清、多菌灵各浓度对褐飞虱杀伤作用不明显。毒力测定结果表明，异稻瘟净对褐飞虱2、3龄若虫的毒力回归式为Y＝-3.7124+3.3248X(r=0.9742*)，致死浓度LC50=417.28 mg/kg。

Insecticidal Effects of Paddy Field Fungicides on Nymphs of Rice Brown Planthopper

Eight common paddy field fungicides with five different concentrations were used to analyse their insecticidal effects and toxic determination on 2nd - 3rd instar nymphs of brown planthopper (BPH). 40% IBP EChad obvious insecticidal effects on 2nd- 3rd instar nymphs of BPH at the concentration of 656. 25 mL/hm2. 20%Tolclofos-methyl EC also had a significant killing role from the 3rd day at 750 mL/hm2; 25% Yekuling WP (9 kg/hm2 ). 5% Jinggangmycin SP (7. 5 L/hm2). 20% Tricyllazole WP (6 kg/hm2) and 20% Yeqingshuang WP (6 kg/hm2) had no obvious insecticidal role to 2nd-3rd nymphs of BPH at the lst day after spraying, but had greater insecticidal effect from the 3rd day on. While there are no siginificant mortality of BPH after spraying 75%Chlorothalonil WP and 50% Carbendazin WP at above five concentrations. The result of toxic regression expressionof the 40% IBP EC to 2nd- 3rd nymphs of BPH was determined.