Study On Host Volatiles Regulating Preference Selection Behavior Of Spodoptera Frugiperda

Spodoptera frugiperda,a grasshopper,belongs to Lepidoptera Noctuidae,which is an omnivorous and migratory pest native to tropical and subtropical America.After the invasion of China,it quickly spread to many provinces,posing a great threat to the production of many crops in China,especially corn.Like many herbivorous insects,S.frugiperda will rely on the volatiles of host plants to locate its host,thus providing a suitable place for its feeding,mating,oviposition and other behaviors.In this paper,the effects of different corn varieties on oviposition selectivity of S.frugiperda in grassland were studied by field cage experiment.Through indoor behavior selection,the components of the behavior regulator of S.frugiperda were preliminarily explored,and the preliminary formula of the behavior regulator of S.frugiperda was designed.At the same time,the volatiles of different corn varieties in different growth periods and different periods were collected,and the release rhythm and difference of volatiles among different corn varieties were understood.The main results are as follows:（1）There are significant differences in the oviposition selectivity of S.frugiperda to four kinds of corn.Facing the corn of the same variety with different growth periods,S.frugiperda prefers to lay eggs in the stage of small trumpet,followed by the stage of big trumpet,and dislikes to lay eggs in the stage of tasseling.The spawning amount is the highest in the big bell mouth stage,followed by the seedling stage and the small trumpet stage,and the lowest in the tasseling stage.There was no significant difference in oviposition preference of S.frugiperda to conventional corn,sweet corn and waxy corn in the same stage.The oviposition of conventional Wugu 3861 was the highest in seedling stage,small trumpet stage and big trumpet stage,and the oviposition of conventional Zhengdan 958 and waxy corn varieties was the highest in tasseling stage.（2）Through the behavior selection of different compounds,7 compounds out of 27 compounds were found to have behavior regulation effect on female adults of S.frugiperda.Among them,Hexyl acetate,Cis-3-Hexenyl Acetate,α-farnesene,α-pinene and（+）-Dipentene are the attractants,and Nerolidol and β-pinene are the repellents.The five compounds can regulate the behavior of male adults of S.frugiperda,with α-terpinene as the attractant and Methyl anthranilate,Nerolidol,TMTT and（+）-Dipentene as the repellent.（3）22 female insect attractant formulations,3 female insect repellent formulations,2 male insect attractant formulations and 8 male insect repellent formulations were designed through effective compound components.Among them,the formula of α-farnesene +（+）-Dipentene + α-pinene（concentration 10 mg/ml）at the ratio of 1: 1: 1 has the best effect on attracting female insects.The formula of nerolidol + β-pinene（concentration 10mg/ml）at the ratio of 1:1 has the best repellent effect on female insects.The formula of α-terpinene0.01mg/ml has the best effect on attracting male insects.The formula of nerolidol +（+）-Dipentene（concentration 10mg/ml）at the ratio of 1:2 has the best repellent effect on female insects.（4）Volatiles of different corn varieties in different growth periods and different periods were analyzed.The results showed that there were significant differences in the contents of most common volatiles among the three periods of different corn varieties and different growth periods,and the volatiles in the night and evening were slightly more than those in the morning.Among the four corn varieties,sweet corn identified the most volatile species,followed by conventional corn and waxy corn.There are 43,65,64 and 58 common compounds in four corn varieties at seedling stage,small trumpet stage,big trumpet stage and tasseling stage,respectively,and the contents of most common compounds are significantly different.Among the four growth stages,the volatile species in the small trumpet stage is the most diverse,followed by the bigtrumpet stage,and the seedling stage and the tasseling stage are the least.The above results can provide theoretical basis for controlling the behavior of S.frugiperda in grassland by using host volatiles,and lay a foundation for monitoring and controlling S.frugiperda in grassland.