Biological Mechanisms Of Populus Nigra L. Plant Attracting Insects (Lepidoptera)

Many insects of Lepidoptera are important agricultural pest. Helicoverpaarmmigera bring giant harm to agricultural produce.In our country,people had used withered black poplar branches to attract Helicoverpa armmigera long ago. But the reason that withered black poplar branches attract Helicoverpa armmigera is not clear. The article study on the reason in behavior and physiology .Field test showed that the spectrum of attracting insects of withered poplar leaves was very wide, and the spectrum includes more than 60 species belonging to 7 orders 21 families. Among these species,the number of insect of Noctuidae was the largest.Comparied with mixture branch and similar branch,the attracting effect of poplar branch was the best.The attracting result also showed that factors of poplar branch attracting moths were not physical factors,but chemical factors.Dosage reaction showed that the spectrum of attracted insect of extracting distillation is wider than the spectrum of withered poplar leaves. The attracting ability of extracting distillation increased with dosage increasing, but it will stop when the dosage is big enough.The odor was extracted by stream distillation and gas adsorption and further identified by gas chromatography-mass spectrometry. By stream distillation, nineteen components were identified from the extracted odor, most of components belong to alcohol, phenol, aldehyde. And their number of C atomic is less than 16.Nine components are public. Except the components of green leave odonmany components is the attracting bait of others pest.The result of Electroantennograms(EAGs) show that the volatiles of withered poplar has attracting activity. Hexanoic acid,phenylacetaldehyde, Hexanal and Benzaldehyde elicited the largest EAG responses among the volatiles compounds. The EAG response of Hexadecanol.(E)-caryophyllene were weak.Males were sensitive to the volatiles of withered poplar than females.The EAG response of mated female is higher than virgin moth.Field test showed that some samples have good attracting effect than CK.But the effect is lower than the effect of withered black poplar branches. Both single compounds and mixed compounds can not increase the attracting effect of sex pheromone.The next aim of this test is to selecting active compounds in the laboratory and field.In the laboratory, the odor emitted by black poplar branches has no effect on the mating, but can lure moths to hide and deposite more eggs evidently. Volatiles from black poplar bundles and bundles themselves have no influence on the prophase for oviposition, persistent days of laying eggs and longevity but can enhance the moth to deposit more eggs significantly. We can conclude that some compounds of volatiles of withered poplar can stimulate moth to deposite more eggs. Maybe this is the reason of withered black poplar branches to attracting Helicoverpa armmigera.