A new type of pest control machine was developed by the Kagoshima Institute for Agricultural Development and the Matsumotokiko Corporation. In the second crop of the tea season, the effectiveness of this machine in reducing feeding damage from tea green leafhoppers, Empoasca onukii Matsuda, was investigated in a pesticide-free tea field. We compared the number of collected leaf hoppers, the length of new shoots, degree of feeding damage by leaf hoppers and tea yields between treated plots and untreated plots in order to evaluate the effects of the treatment by this machine. Treatment with this machine was conducted once or twice in a week from bud break to plucking. As a result, the number of collected leaf hoppers was significantly different after two or three times of treatment and the degree of feeding damage in treated plots was statistically lower than that of untreated plots.

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Aroma extract dilution analysis (AEDA) has revealed potent odorants in Japanese tea cultivars of ‘Sofu’ and ‘Yabukita’. AEDA showed that 1-octen-3-one, linalool, 3-methylnonane-2,4-dione, β-damascenone and (Z)-methyl jasmonate were the most prevalent odorants in the tea cultivar of ‘Sofu’; while 6 odorants namely (Z)-1,5-octadien-3-one, 4-mercapto-methyl-pentanone, linalool, (E,E)-2,4-nonadienal, 3-methylnonane-2,4-dione and β-damascenone were key odorants in the tea cultivar of ‘Yabukita’. Aroma profiles of the tea cultivars of ‘Sofu’ and ‘Yabukita’ have been shown as spider graphs, which were based on the results obtained from odor qualities and the flavor dilution factors. Those clarified that fruity and floral odors contributed to the characteristic aroma of ‘Sofu’. Besides, the results showed that methyl anthranilate (fruity) and (Z)-methyl jasmonate (floral) were key factors for formation of its characteristic aroma.

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The activation of mucosal immunity by drinking of green tea extraction with a high EGC ratio was positively correlated with the activation of macrophage phagocytosis by the green tea extract. Therefore, we estimated the effect of green tea extract derived from different cropping periods or cultivars using phagocytic activity of macrophage-like cells, so that the necessary condition to activate the macrophage phagocytosis was over 2 ratio of EGC to EGCG. The tea leaves harvested in late seasons include many catechins; therefore, the use of the late season leaves is effective way to get many catechins. Moreover, catechins content in tea leaves differs among cultivars. In this study, “Yutakamidori” was high EGC content cultivar.

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To evaluate the freezing resistance of tea shoots during winter and early spring, the electrolyte leakage from tea shoots after cold treatment was assessed by using a conductivity meter. Increase in electric conductivity reflected tissue injury immediately after cold treatment. The variation in electric conductivity indicated the differences in cold resistance among cultivars (‘Sofu’, ‘Yabukita’, and ‘Fushun’), in addition to the changes in cold resistance from winter to early spring and differences in cold resistance based on whether or not medium pruning treatments were performed.

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The freezing method is most effective for frost protection in tea production; however, preparation of enough water for application has been difficult. Recently, Zero-control, a new water-saving-type sprinkler system that helps maintain the tea canopy temperature above its critical temperature by controlling water application via a temperature sensor, has been developed. In this study, we report the establishment and extension of Zero-control adapted to a 100-second rotation application system popular in the Soo region of Kagoshima Prefecture. In the test tea field, Zero-control maintained the tea canopy temperature above -1℃ after freezing, and no frost damage was observed in the spring of 2011, which had frequent hard frost. In addition, water consumption by Zero-control was 57% less than that by the 100-second rotation application system. For the use of Zero-control, both sensitivity and setting location of the temperature sensor of the system are important, especially in tea fields that have a temperature gradient. Because it has been proven that Zero-control can protect tea shoots from frost damage and save water effectively, many tea farmers have introduced Zero-control in their sprinkler systems. We taught practical use of Zero-control to tea farmers. After water application using Zero-control was started in the autumn of 2011, shortage of water supply and frost damage of tea shoots have not occurred.

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The practicality of an improved synthetic sex pheromone lure for the yellowish elongate chafer, Heptophylla picea Motschulsky, was evaluated in tea fields in Shizuoka Prefecture, Japan. E-isomer level in the synthetic pheromone (Z)-7,15-hexadecadien-4-olide is 1% in the new products and 3% in the existing products; thus, purity of the pheromone in the new products is higher than that in the existing products. The number of male adults of H. picea attracted by pheromone traps (New Windspac®, Fuji Flavor Co., Ltd.) with the new products were, on an average, 2.4 times, and a maximum of 5.0 times, the number of male adults attracted by traps with the existing products, the new products were sufficiently effective for the monitoring . However, the number of male adults trapped using a new product was less than that trapped using a neighboring light trap, and the peak time of capture prevalence was earlier than that of the light trap. The number of H. picea attracted by 4 kinds of trap-set: 2 types of lures times 2 types of traps were counted in a tea field. Trap types did not significantly affect the number of H. picea, although the combined New Windspac® trap with the improved new lure attracted the most number of beetles. These results suggested that the New Windspac® trap with the improved new lure was sufficiently effective for the monitoring of H. picea in tea fields.

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Aroma extract dilution analysis (AEDA) has revealed potent odorants in the headspace above infused roasted green tea (Hojicha) and in the infusion. AEDA showed that 2-ethyl-3,5-dimethylpyrazine was the most prevalent odorant in the headspace above infused Hojicha; while 4 odorants, namely, 2-ethyl-3,5-dimethylpyrazine, 2-acetyl-2-thiazoline, β -damascenone, and 4-hydroxy-2,5-dimethyl-3(2H)-furanone were potent odorants present in the infusion. Aroma profiles of the headspace and the infusion have been shown as spider graphs, which were based on the results obtained from odor qualities and the flavor dilution factors. Those clarified that sweet, roast and green odors strongly contributed to Hojicha aromas isolated from the headspace and the infusion.

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The biosynthetic pathways of flavonoids and the enzymes involved in those pathways are shown in Figures 1, 2, 3, and 4, and Table 1. The flavonoids in the metabolic maps include flavones, flavanones, dihydroflavonols, leucoanthocyanidins, flavonols, anthocyanidins and flavanols (catechins).

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