四种杀虫剂LC25对Q型烟粉虱成虫取食行为的影响

[目的]利用刺吸电位技术(electronic penetration graph,EPG)研究Q型烟粉虱(Bemisia tabaci)成虫对吡虫啉、吡蚜酮、螺虫乙酯和溴氰虫酰胺4种杀虫剂LC25处理24 h番茄苗的取食行为,探明内吸性杀虫剂亚致死剂量对烟粉虱成虫取食行为的影响.[方法]以无农药暴露史的Q型烟粉虱成虫...

Effects of Four Insecticides LC25 on Feeding Behavior of Q-Type Bemisia tabaci Adults

【Objective】The objective of this study is to investigate the effects of sub-lethal concentration imidacloprid, pymetrozine, spirotetramat, and cyantraniliprole on the feeding behavior of Q-type Bemisia tabaci adults on tomato seedlings, the feeding behaviors of insects were recorded by the thorn-suck potential technique electronic penetration graph (EPG) after treating with four insecticides LC₂₅ for 24 h.【Method】The Q-type B. tabaci adults that were not exposed to pesticides were used as test insects, and Fenyin No.3, the main tomato variety was employed as the test plant. These plants fed by whitefly were well managed in the lab with hydroponic condition for the experiment. The sub-lethal concentration LC₂₅ of four systemic insecticides was determined by bioassay. On this basis, 13 non-phloem and 8 phloem parameters of B. tabaci adults feeding host were monitored by EPG. Moreover, the leaf piercing suction holes were observed with microscopy. No pesticide treatment was set as control (CK).【Result】The rank of LC₂₅ values of whitefly adult to four insecticides was cyantraniliprole>pymetrozine>imidacloprid>spirotetramat. Within 8 h monitoring of whitefly on plants, the six kinds of waveforms, including non-probing wave (np), pathway phase wave (C), potential drop wave (pd), phloem activities (waveform E: E1 and E2), and xylem activities wave (G), were occurred after the treatment of LC₂₅ of each pesticide. The number of np wave in the cyantraniliprole treatment was largest in all treatments, followed by the spirotetramat treatment. There was no significant difference between the two above pesticides (P>0.05), but was significantly higher than that in CK and imidacloprid treatments (P<0.05). The total duration of C wave and G wave was longest in CK treatment and shortest in cyantraniliprole treatment, and there was significant difference between the two treatments (P<0.05). The total duration of pd wave was longest in CK treatment and shortest in spirotetramat, there was significant difference between the two treatments (P<0.05). The total duration of F wave was longest in spirotetramat and shortest in imidacloprid, and there was significant difference between the two treatments (P<0.05). The total duration of E1 wave and E2 wave was 20.52 and 50.60 min on the phloem of the CK treatment, respectively. There was significant difference with treatments of imidacloprid and cyantraniliprole in the two indicators (P<0.05). However, there was no significant difference with pymetrozine and spirotetramat treatments in the total duration of E1 wave indicator (P>0.05).【Conclusion】The refusal effects on the feeding behavior of Q-type B. tabaci adults have been found by four insecticides with LC₂₅ treatments. It provides a theoretical basis for the feeding refusal mechanism study of the sub-lethal effects of B. tabaci and piercing-sucking mouthparts pests on the four pesticides and pest control.