Effects Of Volatiles From Sunflower Head On Host Plant Selection Of European Sunflower Moth Homoeosoma Nebulellum

European sunflower moth Homoeosoma nebulellum Hubner is the most serious pest on sunflower flower and seeds. In order to study the effects of volatiles from sunflower head on host plant selection of H. Nebulellum,12 typical different sunflower accessions (including 9 edible sunflower accessions,3 oil sunflower accessions) were firstly selected from past several years results to explore the relationship between sunflower flowering phenology and host plant selection of H. Nebulellum on field by using infestation index of seed. Then the volatiles from the sunflower head were collected by solid-phase microextraction (SPME) and analyzed by GC-MS to obtain the chemical components. The main active components from volatiles of sunflower head were further identified by LAG electrophysiological responses and Y-tube behavioral bioassays. The results will help to reveal the mechanism of chemical communication in.host plant selection of European sunflower moth and provide the basis for breeding resistant sunflower cultivars and exploiting new control methods in future. The main results were as follows:1. The sunflower accessions in R5.1-R5.2 flowering stage (opened tubular florets equal to 10～20 percent of whole head) was damaged heavily than in other flowering stages within 12 chosen sunflower accessions as a result of the sunflower accessions in R5.1-R5.2 flowering stage meeting with the peak of emergence and oviposition of sunflower moth adults. Moreover, the oil sunflower accession of MGS in R5.I-R5.2 flowering stage showed higher infestation index of seed than other sunflower ones although MGS was already identified as a higher resistance accession in previous research Meanwhile, the confectionery Xinghuo evaluated as a higher susceptible accession with longer development period showed the lowest infestation index of seed because of unopened flowering when adults of sunflower moth occurred. Therefore, planting time should be made according to the flowering phenology of different accessions in order to alleviate the damage by avoiding the adults of sunflower moth in practice.2. The volatiles from sunflower head were collected and analyzed by SPEM and GC-MS which included terpenoid compounds as the main components both for higher susceptible accession of LD5009 and higher resistant accession of Neikuiza 3. The terpenoid from LD5009 accounted for about 79.8%, such as beta-Myrcene, Limonene, alpha-Pinene, Camphene, etc.; and then alkane accounted for about 15%, alcohols accounted for about 4% and esters such as Bornyl acetate accounted for about 1.2%. Meanwhile, the terpenoid from Neikuiza 3 accounted for about 83.4%, such as beta-Myrcene, Limonene, alpha-Pinene, Camphene, etc.; and then alkane accounted for about 11%, alcohols accounted for about 4.3%, esters such as Bornyl acetate accounted for about 0.9% and ketones accounted for about 0.4%.3. Several main volatile components (Eucalyptol, Camphene, alpha-pinene, Limonene, Bornyl acetate) from sunflower head were chosen to conduct EAG electrophysiological responses and Y-tube behavioral bioassays to female adults of sunflower moth. Two kinds of compounds Limonene and Bornyl acetate were identified as the active components for antennae of female sunflower moth. Meanwhile, the optimal concentration eliciting the electrophysiological and behavioral responses for female adults of sunflower moth is consistent with Limonene at concentration of 10μL/mL and Bornyl acetate at concentration of 0.01μL/mL were electrophysiologically optimum to antenna of female adults as well as evokinged the strongest responses for female adults of sunflower moth.