Identification And Study On Three Plant Volatile Compounds Of Attracting Mythimna Separata (Walker)

The oriental armyworm,Mythimna separata,which is distributed widely in eastern Asia and Australia.Larva can eat maize,wheat,rice and several food crops with the broad host range,and incidences of damage have become more frequent during the recent decades,which makes it an important agricultural pest.Chemical control against M.separata for a long time has increased pesticide resistance and the adaptability of the different environment.Therefore,it is urgent to develop new effective control strategies for this pest.In recent years,integrated pests management in agriculture and forestry have already been proved to be achieved via the application of semiochemicals.It is successful to use mass heromone bait to controll and kill many agricultural insect pests.There are more research about plant volatiles and insect sex pheromones in chemistry pheromone.Volatiles from host plants was proved to play an important role in regulating phytophagous insect behavior,such as orientation and identification to host plants,feeding or oviposition.We used volatiles from Pterocary astenoptera C.DC,Salix babylonica and Zea may L.to monitor and control M.separata.We applied the methods of GC-EAD and GC-MS to extract and identify the main compounds.We tested responses of M.separata to plants volatiles by EAG,wind-tunnel and trap,and thus the results evaluate the possibility compounds of plants,which provided a theoretical basis for developing plant attractants on M.separata.The main results showed as follows: 1.Behavioral response of M.separata to P.stenoptera leaves,S.babylonica leaves,Z.may silks and plant headspace collectionsBehavioral responses of M.separata male and female to wilted leaves from P.stenoptera and S.babylonica,fresh silks from Z.may and their headspace collections were studied in the wind tunnel.Significantly more females and males were elicited behavioral responses to wilted leaves of P.stenoptera and S.babylonica and fresh silks of Z.may than control(n-hexane).P.stenoptera headspace collection had the best effect on female moths among three headspace collections.Significantly more male moths were elicited behavioral responses to wilting leaves of S.babylonica than that of control.M.separata approaching to S.babylonica and Z.may headspace collections within 5cm were significant higher than control.2.Analysis and identification of P.stenoptera leaves,S.babylonica leaves and Z.may silks volatile compoundsThrough GC-EAD and GC-MS analyses,EAG-active compounds identified from the volatile of P.astenoptera have ?-Pinene,beta.-Pinene,beta-Caryophyllene,Methyl salicylate,3-Carene,?-Farnesene,beta.-Ocimene,Benzyl alcohol and Benzaldehyde.EAG-active compounds identified from the volatile of S.babylonica have 1,2,3-Trimethylbenzene,2-Pentylfuran,Phenylethyl Alcohol,trans-2-Nonenal,Hexanal,Salicylaldehyde,?-Farnesene,trans-2,cis-6-Nonadienal,beta.-Ocimene,cis-3-Hexen-1-ol,Benzothiazole,Benzyl alcohol,Benzaldehyde,beta-Caryophyllene.EAG-active compounds identified from the volatile of Z.may silk have 1-Heptanol,Methyl salicylate,2-Methylbutyraldehyde,2-Nonanol,3-Methyl-1-butanol,3-Ethylacetophenone,4-Ethylbenzaldehyde,4-lsopropylbenzyl alcohol,Longifolene,Decyl aldehyde,Geraniol and Phenylacetaldehyde.3.Behavioral response of M.separata to P.stenoptera leaves,S.babylonica leaves and Z.may silks volatile compoundsWhen 29 plant volitile compounds was the dose of 10?g/?l,EAG responses elicited were significantly greater than the solvent controls.The hightest EAG responses of virgin males were elicited by trans-2,cis-6-Nonadienal,following by Phenylethyl alcohol,trans-2-Nonena,cis-3-Hexen-1-ol and Decyl aldehyde.The hightest EAG responses of virgin females were elicited by Benzyl alcohol,following by trans-2,cis-6-Nonadienal,1-Heptanol,Phenylethylalcohol,trans-2-Nonena,cis-3-Hexen-1-ol,2-Methylbutyraldehyde,4-Ethylbenzaldehyde,Decyl aldehyde and Phenyl acetaldehyde.What's more,we test EAG dose-dependent response of the main 13 EAD-active compounds.The amplitude in EAG response elicited by chemical compounds was in the range of 0.24 to 2.87 mV,as revealed by single compound increased with the concentration of the compound from 0.01-10?g/?l,and decreased from 10-100?g/?l.In the single compound bioassays,all compounds can make virgin female and male moths flying upwind.Behavior percentage of moths trending the same compound are basically identical.More number of females land at the range of 5cm of the source with cis-3-hexen-1-ol,Ocimene,Methyl salicylate,Phenylethyl alcohol,trans-2-Nonenal,trans-2-cis-6-Nonadienal and 2-Pentylfuranthan than control significantly.More males flew upwind toward 1-Heptanol and cis-3-Hexen-1-ol was significantly different from response than control significantly.However male land at the source toward Methyl salicylate was significantly higher than control.In the several compounds mixed with the same ratio bioassays,M8,M6 mixtures from P.stenoptera,M14,M6 mixtures from S.babylonica and M12 mixtures from Z.may had the best attracting effect on virgin females and males,which behavior percentage of landing at the source is significant higher than control.4.Outdoor trap experiment to M.separata by P.stenoptera leaves,S.babylonica leaves and Z.may silks volatile compoundsIn the net house trap experiments,headspace collection of S.babylonica attracted small number of M.separata moths,but not significant difference than control.Methyl salicylate attracted M.separata moths most,followed by Benzaldehyde,trans-2-cis-6-Nonadienal,Phenylethyl amone single compounds.M8,M6 mixtures from P.stenoptera and M14 mixtures from S.babylonica had a stable attracting effect on a small amount moths.The results of field trap experiments showed that three plant headspace collections barely attracted M.separata moths.A few of M.separata moths were attracted by single compound,and two multi-componds mixtures had almost no effect on attracting.