Bioactivity Study Of Sex Pheromone And Its Additives Of Phthorimaea Operculella Zeller

The potato tuber moth,Phthorimaea operculella Zeller(Lepidoptera: Gelechiidae),drilling damage to Solanaceae plants,is an important pest of potato and tobacco.Chemical control is still the most effective way to control P.operculella,which poses a threat to the ecological environment and food safety.Insect sex pheromones has the advantages of strong specificity,low dosage and environmental friendliness.Our research focuses on the P.operculella sex pheromone and its additives.Basing on chemical ecology,combined with gas chromatography-mass spectrometry(GCMS),antenna electrophysiology(EAG)and field trapping,to explore the application factors of P.operculella sex pheromone systematically.This paper aims to providing theoretical basis and technical support for the using of sex pheromone and its related attractants to control P.operculella.The main results of onr study as follows:1.Ultrastructure of antenna sensilla of P.operculellaThe scanning electron microscope was used to examine ultrastructure types and distribution of antennal sensilla of potato tuber moth.Nine morphological sensilla types were observed on both sexes: sensilla trichodea,sensilla basiconica,sensilla chaetica,sensilla styloconica,sensilla cavity,sensilla coeloconica,sensilla auricillica,B?hm's bristle(two subtypes),and sensilla squamiformia.The sexual dimorphism have found in the first four sensilla types.2.Extraction and activity determination of sex pheromone under laboratory conditionThe P.operculella sex pheromone,feeding on potato or tobacco,extracted by solventextraction method,and compared with standards by GC-MS.It was found that the main sex pheromone compounds including E4,Z7-13: AC(PTM1)and E4,Z7,Z10-13: AC(PTM2)in potato tuber moth sex gland in China.The titer and relative ratio of P.operculella sex pheromone compounds secreted by female adult moth have different between different host population,while,the relative electroantennogram(EAG)responses trend of P.operculella to the synthesized sex pheromone components were the same directly stimulated.3.Field screening and optimization of P.operculella sex pheromoneThrough screened and optimized in different host fields,the results showed that the higher attracting activity ratio were PTM1: PTM2 = 1:4-1:7,and PTM1: PTM2 = 5:1-4:1 in the potato field and tobacco field,respectively.The most attractive lure was made of butyl-rubber loaded with n-hexane loading 100 ?g of sex pheromone;Traps with sticky boards worked better;The most effective distance between the two traps is 15 m;The trap should be suspended above the host crop canopy,and the height can be adjusted according to the height of the crop without affecting the growth and development of the crop.The above studies provide technical details necessary for the mass trapping of P.operculella sex pheromones.4.Synthesis and bioactivity determination of sex pheromone analoguesBasing on the structure of sex pheromone compounds,11 sex pheromone analogues were designed and synthesized.After characterization,their bioactivity was measured under the laboratory and field conditions.We have found that(4E,7Z)-trideca-4,7-dien-1-yl 2-bromopropanoate,(4E,7Z)-trideca-4,7-dien-1-yl 3-methylbut-2-enoate,(4E,7Z)-trideca-4,7-dien-1-yl(E)-but-2-enoate,(4E,7Z)-trideca-4,7-dien-1-yl 4-methylbenzote and(4E,7Z,10Z)-trideca-4,7,10-trien-1-yl 2-bromopropanoate can be used as pheromone substitutes.Particularly,(4E,7Z,10Z)-trideca-4,7,10-trien-1-yl 2-bromopropanoate has the most stable activity.The sex pheromone analogues(4E,7Z,10Z)-trideca-4,7,10-trien-1-yl 2-bromopropanoate and(4E,7Z,10Z)-trideca-4,7,10-trien-1-yl(E)-but-2-enoate can be used as stable synergist of sex pheromone in the field trapping experiment.Analogs(4E,7Z)-trideca-4,7-dien-1-yl 2,2-difiuoroacetate,(4E,7Z)-trideca-4,7-dien-1-yl 2,2,2-difiuoroacetate,(4E,7Z,10Z)-trideca-4,7,10-trien-1-yl 2,2-difiuoroacetate and(4E,7Z,10Z)-trideca-4,7,10-trien-1-yl 2,2,2-difiuoroacetate can be used as antagonists when they are added in high quality proportion.5.Influence of plant volatiles on sex pheromonesThe EAG responses of P.operculella male and female to 15 plant volatiles were evaluated on the laboratory condition,which indicated significant differences between plant volatiles as well as between sexes.There were dose-effect relationships between female adult EAG responses and plant volatiles.Plant volatiles were added to sex pheromone traps in a certain proportion to verify their biological activity by trapping test under field condition.The results showed that volatile I1 linalool was used as a stable synergist for sex pheromone;1-octene-3-alcohol and methyl palmitate in a certain proportion can also play a synergistic role.In our study,the P.operculella sex pheromones and its additives were studied systematically,and the additives that could improve the trapping activety of sex pheromones were screened,which provide ideas for the green prevention and control of potato tuber moth.