Abstract:Needle volatiles of Masson pine,Pinus massoniana were obtained by solvent extraction and following vacuum distillation.20 Components were identified from the volatiles with GC and GC-MS.They were mainly monoterpenes,monoterpene alcohols,monoterpene acetates and sesquiterpenes. The roleof the needle volatiles in the selection of oviposition site for the masson pinecaterpillar,Dendrolimus punctatus was investigated with normal and antennectomized female moths.The experiments showed that normal moths depositedmuch more eggs on the pine needles than antennectomized ones.Electroantennogram(EAG)study showed that both sexes of unmated and mated mothshad strong EAG responses to the needle volatiles.The volatiles were fractionated by preparative GC and GC fractions were assayed for EAG activitiesto unmated and mated females.EAG activity was found in the fractionscontaining some of monoterpenes,monoterpene alcohols and monoterpeneacetates.The largest EAG response was elicited by the fraction mainly containing β-pinene.