关键词: 褐飞虱, 杀虫剂药效, 速效性, 持效性, 杀成虫活性, 杀卵活性

Abstract:

【Objective】 Bioactivity assessment of mainstream insecticides against the brown planthopper [Nilaparvata lugens(Stål)] was conducted to choose proper insecticide(s) in field conditions.【Method】We evaluated the bioactivities, short-term effectiveness, persistence of 9 neonicotinoid insecticides and other 10 commonly-used chemicals against BPH at various developmental stages by the rice stem-dipping method. 【Result】 1) Bioactivitiy: the bioactivities of the 19 insecticides differed significantly. Among them, nitenpyram, clothianidin, chlorpyrifos, sulfoxaflor, dinotefuran and cycloxaprid showed the best bioactivities to both 2nd-3rd instar and 4th-5th instar nymphs followed by pyridaphenthione, spinetoram, pymetrozine, isoprocarb and abamectin. However, insecticides such as thiamethoxam, emamectin benzoate, flonicamid only showed some bioactivities against the 2nd-3rd instar nymphs but relatively weak bioactivities against the 4th-5th instar nymphs. And other insecticides such as buprofezin, imidacloprid, thiacloprid, acetamiprid, imidaclothiz showed low bioactivities against both nymph stages. 2)Short-term effectiveness: chlorpyrifos, pyridaphenthione showed the best performance followed by isoprocarb, dinotefuran, nitenpyram, clothianidin. Pymetrozine showed the slowest effectiveness. 3)Persistence: high effectiveness levels of pymetrozine, dinotefuran, nitenpyram, clothianidin, cycloxaprid were maintained over 15 days. Pymetrozine was the best one, and there was no significant difference in the corrected mortalities of BPH reared on rice plants at 0, 5 and 10 days after pymetrozine treatment. 4)Bioactivities against adults: dinotefuran, nitenpyram, clothianidin, cycloxaprid, chlorpyrifos, isoprocarb, pymetrozine showed obvious bioactivities against adults as well as nymphs. 5)Ovicidal activity: chlorpyrifos, nitenpyram, dinotefuran and clothianidin had significant ovicidal activities. Pymetrozine, cycloxaprid, isoprocarb showed no ovicidal activity, but pymetrozine had insecticidal activity against newly hatched nymphs.【Conclusion】 As for the tested 19 insecticides, only 9 chemicals (pymetrozine, nitenpyram, dinotefuran, clothianidin, cycloxaprid, sulfoxaflor, chlorpyrifos, pyridaphenthioneand isoprocarb ) could be used to control BPH. Among them, pymetrozine had the worst short-term effectiveness and the best persistence and obvious bioactivity against different-stage BPH except eggs. Dinotefuran, nitenpyram, clothianidin and cycloxaprid showed good performance in short-term effectiveness and persistence, and the former three were effective to different stages of BPH. Sulfoxaflor had good bioactivity and short-term effectiveness, whose persistence was shorter than that of neonicotinoid insecticides. Either chlorpyrifos or pyridaphenthione could be applied alone or mixed with other insecticides to control BPH. The former one was suitable to cope with the BPH outbreak threat, because it showed the best short-term effectiveness. The bioactivity of isoprocarb was weaker than the neonicotinoids, but its short-term effectiveness was better, which could be used to mix with pymetrozine for pest control. Moreover, three insecticides such as spinetoram, abamectin, emamectin benzoate normally used to control lepidopteran pests also exerted the promising activities against BPH. However, other seven insecticides such as imidacloprid, buprofenzin and thiamethoxam were not appropriate for controlling BPH anymore.

Key words: Nilaparvata lugens, bioactivity, short-term efficiency, persistences, bioactivity against adult, ovicidal activity