Ghemical Ecological And Physical Regulation Of Empoasca Vitis G(?)the Based On Long-range Host Location

Empoasca vitis G the is a major pest and difficult to control in Chinese tea gardens. Application ofpesticides is the main way to control this pest. With the increasingly prominent situation inenvironmental pollution and food safety, people have attached more attention to the pollution-freecontrol of tea leafhoppers. In the paper, based on the mechanism of olfaction and vision in thelong-range hostlocation, the tropism of leafhoppers to monochromatic light, color and plant volatile wasstudied. The light trap, color trap and plant volatile attractant, which were significant attractive toleafhoppers, used to trap leafhoppers in the field would provide reference for the pollution-free controlof leafhoppers in tea gardens.The function and relationship between olfaction and vision and the interference effect of visualstimulation in the long-range hostlocation process of leafhoppers were investigated through theobservation of visual and olfactory organs with scanning electron microscope and the relative bioassays.The results showed that the long-range hostloction of leafhoppers depended mostly on the vision andsmell. The vision played leading roles in this process, and the ambient color and light showed stronginterference. The color character of host plant was studied by the color-difference meter and coloranalysis method. The colors of leaves in different leafage had significantly differences. The leaves ofolder leafage had lower level of yellow intensity. Leafhoppers exhibited highly significant tropism tospecific light and color. With RGB color mode, the most attractive color was screened by the orthogonalexperimental design. The color gold (RGB:255,255,0) was the most attractive color to leafhoppers.Moreover, light of different wavelengths exhibited different attraction, and UVA and violet light weremore attractive to leafhoppers.The release characteristics of volatile compounds in tea plant under varied physical condition wasdetermined by HS-SPME-GC-MS and headspace absorption method. Firstly, the tea shoots with moretender leaves released more terpenoids, in which the amount of β-linalool was the highest. Secondly, thetea shoots with more mature leaves released more green leaf volatiles, in which the amount of(Z)-3-hexen-1-oland (Z)-3-hexen-1-ol acetate were the highest. Finally, the amount of total volatilesreleased by tea shoots with more old leaves was minimum and the amount of β-linalool was the lowest.The composition and release rates of tea plant volatiles in day and night were significantly different inday and night. On one hand, the tea shoots released more types and larger amounts of volatiles duringthe day, mainly esters and macromolecular terpenoids. On the other hand, volatiles released in the nightwere mainly micromolecular terpenoids and the total amounts were lower. Visible changes in thereleasing characteristics of volatiles would happen when tea shoots were damaged by leafhoppers. Therelease amount of total volatiles and induced volatiles clearly increased. The induced volatiles releasedwith a clear day-night rhythm, the release amounts during night was lower than those in daytime.Various volatiles showed different releasing peak period. Tea leafhoppers showed significantly differenttropism to tea shoots with various physiological status. The most attractive tea shoots had more tenderleaves. Based on the composition of volatiles and Y shaped olfactometer bioassays, the key factorsaffected the attractant effects were the composition and the proportion of volatiles. The attractant mixed with (Z)-3-hexen-1-ol、(Z)-3-hexenyl acetate and β-linalool in appropriate proportions could attract tealeafhoppers.Slow release material was the foundation for the application of volatile attractants in the field. Thesuitable formula for plant volatile attractants was screened with sol-gel method in the lab. Thecomparison of three methods: solvent extraction, dynamic adsorption and zNoseTM, was carried out toselected an suitable method for the releasing characteristic of attractants in the sol-gel dispensers.Results showed that the dynamic adsorption method exhibited better precision and accuracy.The effects of light trap, color trap and attractants in capturing tea leafhoppers were investigatedunder field experiments. Compared with conventional light trap, violet monochromatic LED light trapcaptured less natural enemies. Compared with yellow sticky trap obtained from the market, gold stickytrap captured more leafhoppers. The attractants, mixed with (Z)-3-hexen-1-ol、(Z)-3-hexenyl acetate,β-linalool, ocimene and nonanal in appropriate formulas and proportions, showed an effectiveecological regulating function for tea leafhoppers in the field.