Host Selection Of Carposina Niponensis Walsingham

Carposina niponensis Walsingham (Lepidoptera:Tortricdae) is one of the most important pests on fruit trees in China, which can seriously influence the quality of the fruits by drilling and feeding during larval phase. It also causes significant economic loss. The volatiles of host plants play important roles in the behavior of C. niponensis such as host selection, attack, oviposition and reproduction. Antenna is the major organ of the insects to detect host volatiles. Electroantennogram (EAG) techniques and insect behavior method have been widely used in chemical ecology. In order to better understand the host selection mechanism of C. niponensis, a detailed research is required. This research is intended to provide theoretical and scientific basis for controlling C. niponensis effectively.In this paper we focused on the plant volatiles interact with the insect. Solid phase micro extraction(SPME),gas-chromatography-massspectrometry(GC-MS),electroantennogram recording technique(EAG) and insect behavior method were used to confirm the mechanism of host selection of C. niponensis. The main results showed as follows:The SPME results showed that the composition of volatiles in different host plants (immature fruit phase) between the types and content are significantly different. There are twenty, nineteen, twenty-four and eleven kinds of compounds were detected respectively from immature hawthorn fruit, immature crabapple fruit immature apricot fruit and young leaf of apricot tree. The young apricot fruit of volatiles relative content is the highest, about87.4%; the relative content of leaves apricot tree volatiles minimum, at40.99%. a-Farnesene were detected at all most volatiles of immature fruits. Besides, the relative content of a-Farnesene was higher in immature fruit of crabapple and apricot which achieved to more than50%of the volatiles.EAG response of C. niponensis from different host plants (immature fruit phase) showed that different sources of C. niponensis have different EAG values by the same stimulation. C. niponensis from different host plants didn’t show a strong reaction to their host fruit, which means host fruit have little effect to the EAG values. Besides, C. niponensis from different hosts showed a high EAG value to immature hawthorn fruit.EAG values of C. niponensis increased with increasing concentration gradient of four compounds form host plant. Specifically, C. niponensis have higher values with trans-2-hexenol. When the concentration low (10-3μg/μL-1μg/μL), EAG values of C. niponensis to a-pinene and a-Farnesene have showed no significant different. The EAG values increased with the increase of concentration of trans-2-hexenol and ethyl caprylate. The EAG values showed significant increase when the concentration reached to1μg/μL-100μg/μL. Specially, the EAG values of male to trans-2-hexenol is higher than female; While, the EAG values of female to a-pinene, a-farnesene and ethyl caprylate is higher than male. When concentration10μg/μL-100μg/μL, the EAG response of C. niponensis to trans-2-hexenol and ethyl caprylate close to saturation. However, the EAG values still increased with the increase concentration of a-pinene and a-Farnesene.Field trapping experiments showed:mixed using sexual lures and trans-2-hexenol (50μg/μL) showed better results than using sexual lures or other compound independently.