五种常用杀虫剂对灰飞虱繁殖力的影响

Impacts of five insecticides on the productivity of Laodelphax striatellus (Fallén)

为合理使用杀虫剂防治灰飞虱,采用稻茎浸渍法测定杀虫剂氟虫腈、吡虫啉、毒死蜱、三唑磷和高效氯氟氰菊酯对灰飞虱3龄若虫的室内活性,并用LC50、LC75和LC90测定灰飞虱的繁殖力。结果表明,经氟虫腈和吡虫啉处理的3龄若虫和成虫,所产的第2代若虫数均少于清水对照;而经毒死蜱、三唑磷和高效氯氟氰菊酯处理的3龄若虫和成虫,所产的第2代若虫数均多于对照,其中经高效氯氟氰菊酯LC50处理的3龄若虫所产的第2代若虫数最多,比对照多53.3%,极显著高于对照。在尼龙网隔离的水泥池内稻麦套作,接灰飞虱成虫后分别用氟虫腈39.9mL/667m2和吡虫啉53.2mL/667m2处理,第2年的虫量仅为对照的33.5%和64.6%;而用毒死蜱59.9mL/667m2、三唑磷98.6mL/667m2以及高效氯氟氰菊酯99.8mL/667m2处理,第2年的虫量分别比对照多1.73、1.35和1.93倍。

The toxic activity of five insecticides to the 3ra instar nymphs of the small brown planthopper （SBPH）, Laodelphax striatellus （Fallen）, was determined by using rice-stem-dipping method, and impact on the productivity of SBPH was tested with the LC50, LC75 and LC90 of insecticides. Compared with the amount of the second generation of SBPH treated with water, the amounts of SBPH treated with fipronil and imidacloprid were decreased, the amounts of SBPH treated with chlorpyrifos, triazophs and cyhalothrin were increased. The amount of the second generation of SBPH treated with LC50 of cyhalothrin was 1. 533 times of that treated with water, which was significantly different at 0.01 probable level. The numbers of SBPH treated with fipronil （39.9 mL/667m^2 ） and imidacloprid （53.2 mL/667m^2） only were 0.335 and 0. 646 times of that treated with water, and the numbers of SBPH treated with chlorpyrifos （ 59.9 mL/667m^2 ） triazophs （98.6 mL/667m^2 ） and cyhalothrin （99.8 mL/667m^2 ） had increased by 1.73, 1.35 and 1.93 times in the separated rice-wheat intercropping system in the second year.