Extraction And Identification Of Semiochemicals About Holotria Diomphalia Bates

The scarab beetle Holotria diomphalia Bates (Coleoptera: Scarabaeidae) is the predominant species of the white grub underground pests in northeast of China, nowadays, controlling its population mainly by chemical ways. In order to providing theoretical basis for environmentally control, sex pheromone and plant lure volatiles had extracted and identificated of Holotria diomphalia from chemical ecology aspect starting.Wind tunnel test indicated that the volatiles of Ulmus pumila and Ricinus communis have high efficiency to attract Holotria diomphalia. Solid phase micro-extraction (SPME) technique was applied to extract the volatile of Ulmus pumila and Ricinus communis, when Ulmus pumila volatile was extract, different coated fiber have different effect: the DVB/CAR/PDMS fiber have better effect than CAR/PDMS and PDMS fiber; the extract duration and temperature also have influence on the quantity of Ulmus pumila volatile. After the volatile was isolated by GC-MS, 16 kinds of components was identified, main component was 3-hexen-1-ol, acetate (50.35%), minor components were butanoic acid 3-hexenyl ester(15.59%), trans-beta-Ocimene (14.81%), 4,8-dimethyl-1,3,7-nontriene(11.97%), caryophyllene (2.78%) and 3-hexenyl-alpha-methybutyrate (1.84%).The main volatile from intact leaves of Ricinus communis was 3 kinds of different constitution of dibutyl phthalate (87.81%), and dibutyl phthalate has the highest content (61.73%); besides the main volatile, a small quantity of decanamine, N-butyl (5.11%) and morpholine, 4-octadecyl (7.07%) were identified too. When the leaves were broken to pieces, more volatiles were isolated, and 8 kinds of wound-induced volatiles were identified, they are unsaturated hexyl ester,hexyl aldehyde and hexyl-olmostly, among them 3-hexen-1-ol, acetate was the main component, with content of 92.28%.By electroantennogram (EAG) bioassay, hexane was confirmed for the best solvent for sex pheromone extraction of female Holotria diomphalia; the extraction was obtained by two methods: solvent eluting and vessel rinsing, then the extract was isolated and identificated by GC-MS. This two methods get three candidate compounds of sex pheromone: 2,6-Di-tert-butyl-4-methylphenol (A),dibutyl phthalate (B) and 1,2-Benaenedicarboxylic acid, bis (2-methyl propyl)ester (C). The EAG resoponse of Holotria diomphalia to the three candidate compounds were tested, the result showed that, all of the three compounds could evoke obvious EAG response of both females and males beetles by contrast with the control; when the test dosage between 1ng and 1mg, the EAG response of male and female beetles was enhanced gradually with the increasing of dosage; the EAG activity of male beetles to compound A was stronger than female, however, the EAG response to compound B and C had no difference with female and the light period had no influence on EAG response of both females and males beetles. The EAG resoponse of Holotria diomphalia to the major compound of Ulmus pumila and Ricinus communis—3-Hexen-1-ol,acetate,dibutyl phthalate and 1,2-Benaenedicarboxylic acid, bis (2-methyl propyl) ester were tested too. The result showed that, when the test dosage was 1mg, all of the three volatiles could evoke obvious EAG response of both female and male beetles by contrast with the control, and the EAG response of both sexes to the three volatiles had no difference.