| Helicoverpa armigera (Hübner) is a serious pest of cotton in China. It is an important way to control H. armigera (Hübner) that withered Populus simonii Carr. Branches trapping H. armigera (Hübner). Filed and lab bioassay observation of attraction of the volatiles from wilted leaves of Populus simonii Carr for H. armigera (Hübner) were conducted. The main results are as follows:The attractive effect compare of H. armigera (Hübner) to different kinds of trees and weeds in commom in Xinjiang: The attraction of the poplar bundles made from branches of trees and other weeds in the north of Xinjiang were tested to the H. armigera (Hübner), which include Populus simonii Carr, Populus nigra var thevestina [Dode] Bean, Sophora Alopecuraides L, Populus alba var pyramidalis Bunge, Populus×euramericana CL, Populus nigra var italica(Muench)Koehne, Setaria viride L and Chenopodium glaucum Linn.The results showed that these bundles were attractive to H. armigera, and the attractive effect of bundles made of Populus simonii Carr was the best one.The attractive effect of H. armigera (Hübner) to bundles of Populus simonii Carr in field: Field test showed that the spectrum of attracting insects of withered Populus simonii Carr leaves was very wide, and the spectrum includes more than 15 species belonging to 6 orders 9 families. Among these species, the number of insect of Noctuidae was the largest. The amount of male and female moths trapped by the bundles was positive correlated, with most moths captured being females. The attractive effect of 2 years old bundles made of Populus simonii Carr withered 2 days, which put in field like an umbrella and higher than cotton is better. The bundles withered 5 days did not have attractive effect. Field test also showed that the attractive effect will be better if change bundles within 5 days.The attracting activity of the extracts of withered Populus simonii Carr leaves: The behavioral responses of adults H. armigera (Hübner) to the extraction of different kinds of trees in Shihezi by using a flight tunnel demonstrated that virgin females could respond positively to anyone of the volatiles emitted from the withered leaves of the five non-host plants. The attraction of Populus simonii Carr's extraction is best. Populus×euramericana CL could not attract moths. The extraction of Populus simonii Car could not only attract virgin females but also attract mated females and males. Behavioral responses of adults H. armigera (Hübner) to the extraction will be different with different eclosion days and different withered days under the photo-regime of 14L:10D. Some substances in the extraction of Populus simonii Carr have the attractive effect. The attractive effect of the extraction of Populus simonii Carr with 2 withered days leaves (17.8%) is better than the extraction of fresh leaves (4.4%) and dry leaves (3.2%).The electroantennogram responses of CBW to the volatiles: There were no significant differences in amplitude of electroantennogram (EAG) responds between virgin females, mated females and males to the volatiles of withered leaves of Populus simonii Carr. EAG responses of virgin females reached a peak as sotophase progressed to the 7th hr. under the photoregime of 14L:10D. EAG responses of H. armigera to the extraction will be different with different eclosion days, as a whole, the EAG will decrease with eclosion days'increase. EAG responses to the extraction of Populus simonii Carr are significant, which demonstrated that chemical substance it releases has luring effect.The preliminary analysis of the components of the volatiles from withered Populus simonii Carr leaves: A study was reported about the chemical components of the volatilizing odor from Populus simonii Carr leaves. The odor was extracted by steam distillation and further identified by gas chromatograph-mass spectrometry, ten peaks were obtained from the extracted odor, in which nine components were identified. Among these components, the number of alcohols was the largest, so this substance may be has attractive effect. The components are less, this may be mainly caused the leaves are too old and the high temperature during steam distillation resulted losing effect of some components.The preliminary analysis of the mechanism about the attraction of Populus simonii Carr for H. armigera (Hübner): The results show that Populus simonii Carr attracts insects not because it can only provide hiding place for them, but because it is important that chemical substance it releases has luring effect.This concluded that the volatiles from Populus simonii Carr leaves did function as neither ovipositional attractant nor feeding attractant of CBW but finding courtship. |
