Chagyo Kenkyu Hokoku (Tea Research Journal)
Online ISSN : 1883-941X
Print ISSN : 0366-6190
ISSN-L : 0366-6190
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Volume 2010, Issue 109
TEA RESEARCH JOURNAL No.109
Displaying 1-14 of 14 articles from this issue
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Original Articles
  • Control of the Kanzawa Spider Mite, Tetranychus kanzawai Kishida and Pink Tea Rust Mite, Acaphylla theavagrans Kadono and the Residual Effect of Spraying Petroleum Oil Emulsifiable Concentrate just before the Sprouting of the First Crop of Tea
    Tetsuya Yoshioka, Teruki Sakaida, Kentaro Nakazono, yuichi Nitabaru
    2010 Volume 2010 Issue 109 Pages 109_1-109_12
    Published: June 30, 2010
    Released on J-STAGE: August 01, 2012
    DOIhttps://doi.org/10.5979/cha.2010.109_1
    JOURNAL FREE ACCESS
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    Petroleum oil emulsifiable concentrate (POEC) is a commercial acaricide used for the control of Tetranychus kanzawai Kishida in the autumn/winter season. Further, the damage of bacterial shoot blight increases if POEC is sprayed at this time of the year. It is thought that the occurrence of bacterial shoot blight doesn't increase if POEC is sprayed just before the sprouting of the first crop of tea. However, it is suspected that spraying of POEC at this time results in the formation of an oily film that floats on the surface of tea infusion. In this study, we examined the efficiency of spraying POEC at this time of the year in controlling the growth of T. kanzawai and Acaphylla theavagrans Kadono and the residual effect. We obtained the following results: (1) spraying POEC before sprouting of the first crop of tea resulted in effective control of the density of T. kanzawai and A. theavagrans for 1 month or longer, and (2) the oily film was not observed on the surface of the tea infusion. These results indicate that POEC can serve as one of the important control agents of mites when sprayed just before the sprouting of the first crop of tea.
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  • Influence of the Exposure Time after Removing of Covering Materials over Shading Tea Field on the Quality of Gyokuro
    Teruki Sakaida, Tetsuya Yoshioka, Juichi Nitabaru, Kentaro Nakazono, A ...
    2010 Volume 2010 Issue 109 Pages 109_13-109_21
    Published: June 30, 2010
    Released on J-STAGE: August 01, 2012
    DOIhttps://doi.org/10.5979/cha.2010.109_13
    JOURNAL FREE ACCESS
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    We revealed the influences of the exposure time after removing of covering materials over shading tea field for making gyokuro on the quality of made tea.
    As the exposure time increased, the green color of the fresh leaves faded; their total amino acid and theanine contents reduced; and the concentration of dimethyl sulfide, a representative aromatic compound in gyokuro, decreased. In contrast, the catechin content increased. The overall quality of the tea was lowered.
    These results indicated it was necessary to plucking of tea shoots for short time after removing of covering materials over shading tea field.
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  • Contents of Neo-flavored Tea (GABA Kintaro) Containing γ-Aminobutyric Acid
    Yoshiya Shiraki
    2010 Volume 2010 Issue 109 Pages 109_23-109_30
    Published: June 30, 2010
    Released on J-STAGE: August 01, 2012
    DOIhttps://doi.org/10.5979/cha.2010.109_23
    JOURNAL FREE ACCESS
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    The contents of γ-aminobutyric acid (GABA), catechins, theaflavins, caffeine and pheophorbide-a in neo-flavored tea (GABA Kintaro tea) were analyzed.
    1)The amounts of GABA were increased over 1.5mg/g by means of infrared ray irradiation with agitation treatment.
    2)There was a tendency for the amount of catechins to be decreased by this treatment, whereas the amount of theaflavins tended to increase with the same treatment. The composition of these contents in this GABA Kintaro tea was almost the same as that of black tea.
    3)There was a tendency for the amount of caffeine to be decreased by this treatment.
    4)There was a tendency for the amount of pheophorbide-a to be increased by this treatment.
    5)The result of this study showed that the amounts of GABA and theaflavins in this GABA Kintaro tea were higher than ordinary green tea but contained few catechins.It became clear that the amount of pheophorbide-a in this GABA Kintaro tea was less than the standard value established in processed chlorella.
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  • Monitoring Chlorfenapyr in Green Tea during the Manufacturing Process
    Atsushi Takahashi, Yasuhiro Kishi, Hideyuki Ogawa, Kenta Nakajima
    2010 Volume 2010 Issue 109 Pages 109_31-109_36
    Published: June 30, 2010
    Released on J-STAGE: August 01, 2012
    DOIhttps://doi.org/10.5979/cha.2010.109_31
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    In order to clarify the change in the leaves of agricultural chemicals during the green tea manufacturing process, we analyzed chlorfenapyr in tea leaves obtained at each processing stage by using an immunoassay. Chlorfenapyr is a novel broad-spectrum insecticide-miticide registered in many countries for the control of various insects and mite pests. Chlorfenapyr is stable and persistent in the environment. Furthermore, it is widely applied for tea cultivation in Japan. Therefore, we selected chlorfenapyr for analysis in this study. In the unrefined tea (Aracha) manufacturing process, the highest level of chlorfenapyr was 16.5 ppm, which was obtained in tea powder separated from leaves at the secondary drying stage. However, the level at the other processing stages in tea leaves was approximately 9 ppm, and no significant difference in the chlorfenapyr level was detected between the processing stages. After Aracha processing, tea leaves are classified on the basis of their size, shape and color; this is the refined tea (Shiagecha) manufacturing process. After this process, although a high level of chlorfenapyr was detected in bud tea (8.1 ppm) and honcha (on-grade tea; 6.2 ppm), the level in the other classified teas was approximately 4.0 ppm. Thus, this paper shows the difference in the chlorfenapyr level in tea leaves obtained at each processing stage. This indicated that there are significant differences in the agricultural chemical levels between the green tea processing stages.
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  • Development of the Diagnostic Expert System for Tea Processing
    Hitoshi Yoshitomi, Yuichi Yamaguchi
    2010 Volume 2010 Issue 109 Pages 109_37-109_55
    Published: June 30, 2010
    Released on J-STAGE: August 01, 2012
    DOIhttps://doi.org/10.5979/cha.2010.109_37
    JOURNAL FREE ACCESS
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    A diagnostic expert system for tea processing which can presume the cause of the defect of the processed tea was developed to contribute to the improvement of tea processing. This system that consists of some programs can be used through the Internet. The inference engine, the core of the system adopts production system which is well used on artificial intelligence, and is coded by Prolog as the artificial intelligence oriented language. At present, 176 rules for inference have been registered on this system. The system will be able to presume better if more rules are added to the system.
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Technical Reports
  • A Laboratory Method for Rearing Tea Green Leafhopper, Empoasca onukii Matsuda by Using Tea Seedlings as Oviposition Sites and as Food
    Yukio Kosugi
    2010 Volume 2010 Issue 109 Pages 109_57-109_64
    Published: June 30, 2010
    Released on J-STAGE: August 01, 2012
    DOIhttps://doi.org/10.5979/cha.2010.109_57
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    In this study,I have developed a method for rearing tea green leafhopper, Empoasca onukii Matsuda by using tea seedlings. Tea seeds were prepared by incubating tea seeds at 5 ℃ for 30 daysand planted these seeds in agar gel.The germination rate of the seedlings on the 28th postincubation (at 25 ℃) days was 89.5%. When the length of new shoots was 7-8 cm, the seedlings were replanted in a cup containing agar gel. The cups were covered with a plastic cap and used as a rearing case. One adult female was captured from the tea fields and reared on the rearing case. On an average, 34.7 nymphs were found to breed on this rearing case. However, when the number of adult females in the rearing case was increased, the number of nymphs tended to decrease. Rearing of 1-2 adult males and females resulted in the breeding of more than 20 nymphs, ranging from the first to the fifth generation.
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  • Occurrence of Neozygites sp. (Zygomycetes: Entomophthorales) Attacking the Kanzawa Spider Mite, Tetranychus kanzawai (Kishida) in a Tea Field
    Iwao Ishikawa
    2010 Volume 2010 Issue 109 Pages 109_65-109_72
    Published: June 30, 2010
    Released on J-STAGE: August 01, 2012
    DOIhttps://doi.org/10.5979/cha.2010.109_65
    JOURNAL FREE ACCESS
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    An entomophthoraceous fungus, Neozygites sp. attacked the Kanzawa spider mite, Tetranychus kanzawai (Kishida) in a tea field, Hidaka, Saitama Prefecture, Japan. The fungal infections with Neozygites sp. in a population of T. kanzawai occurred in May, June, September and October but did not occur in July and August. The percentage parasitism of spider mites by Neozygites sp. for larvae, nymphs and adults were 0%, 5.5% and 29.6%, respectively in September. Resting spores were azygospores and were found in cadavers of T. kanzawai collected from September to November. Resting spores on the tea leaves germinated from early to late May in a tea field. Resting spores germinated with short germ tube to form a spherical primary germ conidium remaining on germ tube and forming a capilliconidium.
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