Attraction Of Tea Plant Volatiles To Empoasca Vitis And Influencing Factors

Empoasca vitis(G?the) is a serious pest of tea plant in China, which damage seriously and control difficult. Therefore the harmless management based on ecological regulation is urgently needed.. Herein we developed a leafhopper attractant based on the attraction of plant volatiles, investigated the main factors influencing the attraction in tea garden, and screened some attractive volatiles for the predatory lacewing Chrysopa phyllochroma.The comparative importance of visual and olfactory cues in the short-range host location of leafhoppers was investigated in the ―T‖ olfactometer. The results indicated that the visual cues play a leading role in the short-range host location, and the olfactory cues showed a coordinating role. The golden colour sticky board was attractive to the leafhopper, but the attractiveness was affected by the background color of tea shoots. Results also showed that the visual distance of the leafhopper was about 2 m.Thirteen synthetic compounds in the attraction of tea leafhopper were investigated in the laboratory and field. Laboratory results showed that(Z)-3-hexenol,(Z)-3-hexenyl acetate, ocimene and limonene was attractive to E.vitis adults under certain concentrations. Five blends were investigated under laboratory and field conditions. Results showed that blend 5 was best, and the luring efficiency was about 50%.A thermal desorption-gas chromatograph-mass spectrometry(TD-GC/MS) method was developed to measure the trace levels of plant volatile compounds in field ambient air. The spatio-temporal concentration of attractant in the flight tunnel and tea garden were tested, and concentration of volatiles showed a spatial fluctuation with the distance, time and wind direction.All the four compounds of the attractant were detected in the background odor, and their concentration changed in the different seasons. The concentration in summer was about 4-5 folds higher than that in autumn. Meanwhile, the field results were different in various seasons, and the attractive effect in autumn was better than that in summer. The behavioral assay in the field showed that background odor in tea garden can attract E.vitis, and background odor masked attractant to some extent. However, the masking effect can be overcome by increasing the amount of attractant.Electrophysiological and behavioral responses to 10 common plant volatiles were recorded to screen for lacewing-attracting compounds. Three green-leaf volatiles,(E)-2-hexenal,(Z)-3-hexenyl acetate and(Z)-3-hexenol, produced the strongest electroantennographic responses. Weaker responses were observed in six terpenes, ocimene, linalool,(3E)-4, 8-dimethyl-1, 3, 7-nonatriene,(E, E)-α-farnesene, limonene and nerolidol, and to methyl salicylate. Three common plant volatile compounds,(Z)-3-hexenyl acetate,(3E)-4, 8-dimethyl-1, 3, 7-nonatriene, and linalool, were also observed a significant enhance to female oviposition, resulting in a high concentration of eggs.This paper made the visual distance of the leafhopper clear, and an attractive formula was developed. The background odor in the tea garden can mask the attractant in some extent. Three volatiles were screened to attract the predatory lacewing. The results offered theoretical basis for the non-pollution control of the E. vitis.