Resistance Monitoring And Pymetrozine Affects The Courtship In Nilaparvata Lugens(ST(?)L)

Brown planthopper(BPH)is an insect feeding on sucking rice.The BPH populations in China has produced different levels of resistance to different insecticides.As the main insecticide to control brown planthopper,pymetrozine has a unique mechanism of action on the pest and it affects the number of offspring of the brown planthopper.Recently,triflumezopyrim which developed by DuPont is a new type of insecticide(IRAC 4E)and registered in China in 2017.From2015 to 2017,rice stem dipping method was used to monitor the resistance of 34 N.lugens populations to 10 pesticides in China.To pymetrozine,except for a few populations,most of the populations have reached high level resistance and the resistance kept increasing in these 3 years.To dinotefuran,an upward trend was observed,all the field population in 2017 kept in moderate to high resisatance level(24.3-139.5 folds),especially Jinhua population reached 139.5 folds.the resistance of thiamethoxam has been kept in high level,so it was suggested to stop using thiamethoxam to control BPH in the field.Most of the BPH populations were at low resistance levels to nitenpyram,and no obvious difference in these 3 years.All monitored populations reached moderate reisitance levels to sulfoxaflor and chlorpyrifos.BPH populations still kept high resistant to buprofezin and imidacloprid though they were stopped using.Sensitive baseline of Brown planthopper to triflumezopyrim was established using the rice stem dipping method,with LC50 value of 0.064 mg/L and b value of 1.961,all field populations is susceptible to trifluoropyrimand there is no obvious different among the 8 populations.To explore if pymetrozine affected the courtship behavior of BPH,we observe and described the 8 step of copulation in BPH,and found that darkness and pedicel missed might affect the copulation behavior of BPH,BPH can make copulations on different plants not only on rice.In addition,pymetrozine could decrease the percent of succeed mating behavior in BPH.The candidate insecticides to control BPH were also suggested in this research.Triflumezopyrim could be used to control the BPH alternating with pymetrozine,nitenpyram,dinotefuran,sulfoxaflor.Visual,olfactory might affected the courtship behavior in BPH and mechanical movements are disturbed by pymetrozine so that the mating behavior of the brown planthopper is affected,leading to the number of offspring is reduced.This results could provide a new viewpoint for the new insecticides developing and BPH control.