Chagyo Kenkyu Hokoku (Tea Research Journal)

Original Articles

Effects of Use of Frost Protective Fan on Frost Injury to Tea Plants in March 2010 at Makinohara, Shizuoka

Takuya Araki, Kiyoshi Matsuo, Osamu Sumikawa, Daisuke Miyama

2010 Volume 2010 Issue 110 Pages 110_1-110_8
Published: December 31, 2010
Released on J-STAGE: January 09, 2013

DOIhttps://doi.org/10.5979/cha.2010.110_1

JOURNAL FREE ACCESS

Show abstractHide abstract

Serious frost damage to tea plants was observed in Shizuoka prefecture in March 2010. In this report, we present the results of a survey conducted on a tea field in which tea plants were injured by frost on March 30, 2010.
A survey was conducted at a 0.1 ha tea field located in Makinohara, Shizuoka. Two frost protective fans (1.98 kW, 0.9 m diameter triple-blade) were mounted on 7-m-high steel towers installed at the tea field. The fan installed in the southern part of the field was operated continuously, whereas the fan installed in the northern part was virtually inactive because of energy saver control. Temperatures were monitored at 15 cm and 160 cm above the canopy of the tea plants and 7m above the ground. Wind speed and direction were measured at 1.9m above the canopy of the tea plants. Two weeks after the occurrence of frost injury, the canopy shoots were visually inspected in order to evaluate the damage.
The observations and results of the survey can be summarized as follows:
1)Between 2:00 am and 6:00 am on March 30, the nighttime air temperatures at both 15 cm above the canopy of the tea plants and 7 m above the ground dropped below freezing temperature.
2)The frost injuries to the tea plants under the continuous operation of a frost protection fan in an area of 570 m² were classified into four types: 0 (no injury), 1 (frost injury without necrosis), 2 (frost injury with necrosis), and 3 (necrosis). Type 0 accounted for 0% of the tea field area; type 1, 24%; type 2, 37%; and type 3, 39% respectively.
3)The continuous wind generated by the frost protection fan reduced the inversion strength between 15 cm and 160 cm above the canopy of the tea plants. We observed that the temperature inversion was weaker when the fan was operated continuously than when the fan was inactive. However, the area protected by the fans was 260m2 that was determined by the first plucking area of tea shoots.
4)The temperature reduction on March 30 was occurred by a combination of both advective and radiative frost conditions, so that the frost protective fan could not protect tea plants completely against frost injury. However, the using of the fan is effective to avoid delay plucking and to be harvested tea shoots under the severe frost condition.

View full abstract

Download PDF (971K)
Effects of the Application of Coated Urea and Dicyandiamide and Reduction in the Amount of Nitrogen Fertilizer on Tea Garden for Gyokuro

Teruki Sakaida, Tetsuya Yoshioka, Akira Kubota, Juichi Nitabaru, Kenta ...

2010 Volume 2010 Issue 110 Pages 110_9-110_18
Published: December 31, 2010
Released on J-STAGE: January 09, 2013

DOIhttps://doi.org/10.5979/cha.2010.110_9

JOURNAL FREE ACCESS

Show abstractHide abstract

We examined the effect of coated urea and dicyandiamide (Dd) applied during the spring and fall on the yield and quality of tea garden for Gyokuro. Moreover, we examined whether the amount of nitrogen fertilizer could be efficiently reduced while maintaining the yield and quality at the same level as that observed in conventional fertilizer application.
The application of coated urea and Dd during the spring and fall decreased nitrogen leaching to a greater extent than that observed in conventional fertilizer application. This result indicates that Dd inhibits nitrification. In addition, the density of inorganic nitrogen in the soil increased as compared to that after conventional fertilizer application. The yield and quality improved when a conventional amount of nitrogen fertilizer was used because of increase in fertilizer efficiency. Moreover, even if the amount of nitrogen fertilizer was reduced by approximately 20% of the amount conventionally applied, the yield and quality were maintained.

View full abstract

Download PDF (1086K)
Long-term Control of the Mulberry Scale, Pseudaulacaspis pentagona (Targioni), in Tea Fields by Spraying Pyriproxyfen in Winter

Tetsuya Yoshioka, Teruki Sakaida, Kentaro Nakazono, Syogo Fukuyama

2010 Volume 2010 Issue 110 Pages 110_19-110_28
Published: December 31, 2010
Released on J-STAGE: January 09, 2013

DOIhttps://doi.org/10.5979/cha.2010.110_19

JOURNAL FREE ACCESS

Show abstractHide abstract

We examined the long-term control of the mulberry scale, Pseudaulacaspis pentagona (Targioni), in a tea field by spraying pyriproxyfen in winter and determining the effects of spray timing, spray volume, and a combination of medium pruning and spraying. We obtained the following results: (1) the insecticidal activity persisted for approximately 5 months after spraying, (2) no difference was observed in the control effect when pyriproxyfen was sprayed in late January or in late March, (3) the amount of vermination decreased for 3 years when pyriproxyfen spray was combined with medium pruning in the following year, and (4) a similar control effect was observed in the application rates of 1000 L/10 a and 700 L/10 a. Moreover, spraying of pyriproxyfen resulted in the effective control of P. pentagona density for 2 years at all the examinations. These results indicate that when sprayed in winter, pyriproxyfen can serve as an important control agent of the mulberry scale. Because winter is the agricultural off-season for tea farming, it is possible to save on the cost of labor. In addition, the spray frequency of the insecticide can be reduced after achieving long-term density control.

View full abstract

Download PDF (1244K)
Occurrence of Neozygites parvispora (Macleod & Carl) Rem. & Kell. (Zygomycetes : Entomophthorales) Attacking the Yellow Tea Thrips, Scirtothrips dorsalis Hood (Thysanoptera : Thripidae) in the Tea Fields

Iwao Ishikawa

2010 Volume 2010 Issue 110 Pages 110_29-110_36
Published: December 31, 2010
Released on J-STAGE: January 09, 2013

DOIhttps://doi.org/10.5979/cha.2010.110_29

JOURNAL FREE ACCESS

Show abstractHide abstract

An entomophthoraceous fungus Neozygites parvispora attacked the yellow tea thrips, Scirtothrips dorsalis (Hood) in the tea fields, Saitama Prefecture, Japan.The fungal infections with N. parvispora in a population of S.dorsalis occurred in June, July, August, September and October but did not occur in April and May, 1981, 1982. The highest percentage parasitism of S. dorsalis by N. parvispora were 27.2% in August, 1981 and 32.1% in June, 1982. The cadavers with the resting spores were observed on abaxial side of tea leaves in September later, 1982 and in August, 1983. Hibernated resting spores germinated in a tea field, Hidaka city in mid-February, 1985. This is the first report of germination of N. parvispora resting spores in the tea field.

View full abstract

Download PDF (849K)
Tama-ryokucha Luster and Brewed Tea Color Evaluations by Spectrophotometric Colorimetry

Hideo Miyazaki, Sadayuki Akaishi, Toshitaka Uchino

2010 Volume 2010 Issue 110 Pages 110_37-110_47
Published: December 31, 2010
Released on J-STAGE: January 09, 2013

DOIhttps://doi.org/10.5979/cha.2010.110_37

JOURNAL FREE ACCESS

Show abstractHide abstract

Quality of special local tea produced in Western Kyushu Island, Kamairicha (pan fired tea) and Tama-Ryokucha (steamed tea), has been traditionally evaluated by visual judgment. Physical appearance and luster of crude tea, and brewed tea color are important evaluation items for quality. In this study a methodology of spectral reflectance and transmittance was discussed to be used for evaluating the tea quality of luster and brewed tea color instead of the visual evaluation.
The reflectance spectra of luster of crude teas which were divided by visual evaluation of leaf flaw denoted the same tendency regardless of tea kinds, however, the spectra correctly discriminated the leaf flaws at a probability of c.a. 100% as a result of canonical discriminant analysis. In addition, the transmittance spectra also discriminated the colors of brewed tea of both Kamairicha and Tama-Ryokucha at a probability of 100%. Therefore it appears that a numerical conversion of visual evaluation for the leaf flaw and the colors of brewed tea by using the methodology of spectral reflectance and transmittance can be available.

View full abstract

Download PDF (945K)

Short Communication

Effect of Artificial Light on Winter Dormancy and Budding Time of First Flush of Japanese Tea Cultivars

Junichi Tanaka, Atsushi Nesumi

2010 Volume 2010 Issue 110 Pages 110_49-110_57
Published: December 31, 2010
Released on J-STAGE: January 09, 2013

DOIhttps://doi.org/10.5979/cha.2010.110_49

JOURNAL FREE ACCESS

Show abstractHide abstract

During the cultivation of tea (Camellia sinensis L.) in temperate zones, breaking dormancy affects the earliness and synchronization of bud break, and this determines both the profitability of cultivation and the areas that are suitable for cultivation. Therefore, dormancy is an important trait for tea breeding. Previous research revealed a correlation between day length and tea dormancy from late autumn to spring for Japanese cultivars. However, artificial light from streetlamps has not been reported to affect tea growth and development. To clarify the effect of artificial illumination on the budding time of first flush and dormancy of tea, we performed field investigations and examinations using the tea cultivars ‘Harumidori’, ‘Harunonagori’, and ‘Minamisayaka’. Artificial illumination for the examination was provided by fluorescent lights or high-pressure sodium lights. These artificial illuminations did not affect the budding time of first flush or dormancy in the three cultivars. The results indicated that dormancy of tea was not affected by artificial illumination.

View full abstract

Download PDF (900K)
Effects of Pesticides on Adults of Trichogramma dendrolimi Matsumura (Hymenoptera: Trichogrammatidae), an Egg Parasitoid of the Tea Tortrix

Chikara Ishijima, Natsuki Fujita, Yasushi Sato, Makoto Ohtaishi

2010 Volume 2010 Issue 110 Pages 110_59-110_64
Published: December 31, 2010
Released on J-STAGE: January 09, 2013

DOIhttps://doi.org/10.5979/cha.2010.110_59

JOURNAL FREE ACCESS

Show abstractHide abstract

The effects of 27 insecticides, 7 acaricides, and 9 fungicides on Trichogramma dendrolimi were investigated using dry-film methods. The results suggested that non-selective pesticides, such as organophosphates or synthetic pyrethroid insecticides, and insecticides against pests that infest new shoots were harmful to adult females of T. dendrolimi. In contrast, most insect growth regulating (IGR) insecticides, acaricides, and fungicides were either harmless or only slightly harmful to adult females of T. dendrolimi.

View full abstract

Download PDF (755K)

Short reports of Frost damage in 2010

Field Survey of Tea Bush Surface Temperature and Typical Cases in Severe Frost Damage on March 30, 2010 on the Makinohara Plateau in Shizuoka Prefecture

Kiyoshi Matsuo, Takuya Araki, Tsuyoshi Okamoto

2010 Volume 2010 Issue 110 Pages 110_65-110_73
Published: December 31, 2010
Released on J-STAGE: January 09, 2013

DOIhttps://doi.org/10.5979/cha.2010.110_65

JOURNAL FREE ACCESS

Show abstractHide abstract

Many tea fields in Shizuoka suffered severe frost damage on March 30, 2010. The minimum teabush surface temperatures in eight tea fields were investigated. Without any anti-frost equipment, the surface temperature was near -7.5°C . With frost fans, they were between -5.8°C and -3.4°C . Infields equipped with sprinklers, they were between -2.7°C and -2.0°C . We present nine photos of the typical frost damage with detailed descriptions.

View full abstract

Download PDF (1181K)
Injury Distribution in the Tea Field by 2010 Frost Damage in Makinohara, Shizuoka

Tetsuya Oishi

2010 Volume 2010 Issue 110 Pages 110_75-110_78
Published: December 31, 2010
Released on J-STAGE: January 09, 2013

DOIhttps://doi.org/10.5979/cha.2010.110_75

JOURNAL FREE ACCESS

Show abstractHide abstract

This paper describes three investigations of the effectiveness of a frost fan in mitigating the frost damage that occurred on March 30, 2010 in tea fields in Shizuoka. The author presents a detailed map of the distribution of damage that occurred in those fields. The map indicates that the area over which the fan is effective changes with the direction of the westerly wind, and was limited to around 25%-30 % of the designed value.

View full abstract

Download PDF (856K)
Observations of Air Temperature and Leaf Temperature Near the Frost in March 30th 2010 at Shizuoka Prefectural Tea Research Center

Toshikazu Suzuki

2010 Volume 2010 Issue 110 Pages 110_79-110_81
Published: December 31, 2010
Released on J-STAGE: January 09, 2013

DOIhttps://doi.org/10.5979/cha.2010.110_79

JOURNAL FREE ACCESS

Show abstractHide abstract

We conducted a detailed examination of the temperatures of a tea bush throughout the night of severe frost. The temperature was measured at various heights and distances from the frost fans. The surface temperature of a tea bush decrease to -4°C . There little difference between the air temperature at the height of the frost fan motor and the surface temperature of a tea bush.

View full abstract

Download PDF (1059K)
Characteristics in Bud Growth and Tea Bud Hardiness during 2010 Winter Season at Shizuoka Prefectural Tea Research Center

Toshikazu Suzuki

2010 Volume 2010 Issue 110 Pages 110_83-110_85
Published: December 31, 2010
Released on J-STAGE: January 09, 2013

DOIhttps://doi.org/10.5979/cha.2010.110_83

JOURNAL FREE ACCESS

Show abstractHide abstract

The growth stage and degree of cold resistance of tea buds were investigated from autumn 2009 to march 2010. Near the end of March 2010, the growth stage of buds was 2 or 3 days earlier than that in an average year and the 50% lethal temperature increased to -4°C . This characteristic value for tea buds might be had a close relation with the severity of frost damage in the spring of 2010.

View full abstract

Download PDF (859K)
Influence of Pruning After Frost Damage to New Shoots in the Early Stage of Growth on the First Crop in 'Saemidori' Tea Field

Kentaro Nakazono, Tetsuya Yoshioka, Shogo Fukuyama, Akira Kubota

2010 Volume 2010 Issue 110 Pages 110_87-110_90
Published: December 31, 2010
Released on J-STAGE: January 09, 2013

DOIhttps://doi.org/10.5979/cha.2010.110_87

JOURNAL FREE ACCESS

Show abstractHide abstract

We urgently studied the influence of pruning shortly after frost damage to new shoots in the early stage of growth on the subsequent first crop in 'Saemidori' tea bush, which had been medium-pruned in the previous year. Shallow-pruning, defined as trimming off about one node of mother stems, made remaining shoots heavier and increased more than 20 percent of yield than no treatment. This result suggested that shallow-pruning enabled early plucking and was expected to diminish the revenue decline caused by frost damage to new shoots early on growth.

View full abstract

Download PDF (774K)
Characteristics of the Fresh and Processed Tea Leaves in First Crop Seasons from 2006 to 2010

Yuzo Mizukami, Yuichi Yamaguchi

2010 Volume 2010 Issue 110 Pages 110_91-110_94
Published: December 31, 2010
Released on J-STAGE: January 09, 2013

DOIhttps://doi.org/10.5979/cha.2010.110_91

JOURNAL FREE ACCESS

Show abstractHide abstract

In 2010, tea shoots took the freezing damage on March 30 in Shizuoka prefecture. This damage decreased in the yield of fresh tea leaves produced from 14268 ha in the pref. It would be great damage once in 30 years. Besides, this damage brought about 4489 millions yen decrease. Thus, we compiled tea leaves data obtained from the past five years (2006 to 2010) in this short paper. The data included plucking date, characteristics of the fresh and processed tea leaves, as well as the levels of caffeine and catechins. In 2010, the plucking date of early cultivar 'Saemidori' was a few weeks late in comparison with the average year. The characteristics of the tea shoots were small and including terminal bud. Nevertheless, they relatively had many matured leaves. The level of caffeine in the processed leaves was same as that in the other years, but the level of catechins was higher (23.2 %) than those (13% to 19%) of leaves processed in the other years. This may be due to including many matured leaves in the tea shoots plucked. The plucking date of medium cultivar 'Yabukita' was a couple of week late, but the late cultivar 'Okumidori' was plucked as usual. For these two cultivars, significant difference was not found in the characteristics of fresh and processed tea leaves, as well as the levels of caffeine and catechins.

View full abstract

Download PDF (748K)
Sensitivity of the Tea Cultivars Grown at the National Institute of Vegetable and Tea Science in Kanaya to the Spring Frost of March 30, 2010

Akiko Matsunaga, Tetsuji Saba

2010 Volume 2010 Issue 110 Pages 110_95-110_98
Published: December 31, 2010
Released on J-STAGE: January 09, 2013

DOIhttps://doi.org/10.5979/cha.2010.110_95

JOURNAL FREE ACCESS

Show abstractHide abstract

Tea trees planted at the Kanaya Tea Research Station were exposed to spring frost and cold weather on March 30, 2010. In this study, we assessed the frost sensitivity of these tea cultivars. This sensitivity was linked to the time of the bud break. The early bud break cultivars had more severe frost damage than those in the late bud break cultivars. However, ‘Sayamakaori’ had minimal frostdamage as compared to the other cultivars at the same bud break stage. These results indicate that spring frost sensitivity may differ among cultivars at the same bud break stage. It is necessary to develop a novel frost injury-resistance assay for tea cultivars and to develop cultivars that can overcome frost injury.

View full abstract

Download PDF (815K)
Frost Injury of Tea Fields in Makurazaki Tea Research Station of the National Institute of Vegetable and Tea Science on March 11, 2010

Katsuyuki Yoshida, Takuya Araki, Atsushi Nesumi

2010 Volume 2010 Issue 110 Pages 110_99-110_103
Published: December 31, 2010
Released on J-STAGE: January 09, 2013

DOIhttps://doi.org/10.5979/cha.2010.110_99

JOURNAL FREE ACCESS

Show abstractHide abstract

The tea fields of the Makurazaki tea research station, the National Institute of Vegetable and Tea Science, suffered severe frost injury on March 11, 2010, when subfreezing conditions of the tea canopy surface of 'Meiryoku' continued from 1 am to 7 am. The lowest temperature was -2.9°C at 5:00am. Frost injury of tea shoots was observed in early budding tea cultivars which had sprouted before March 8. Varietal differences in the frost injury of each tea cultivar were also observed. The severity of frost injury of each tea field increased as altitude decreased. Recovery of frost-injured tea shoots of early budded cultivars was observed at the end of the season of the first crop of tea.

View full abstract

Download PDF (825K)

Technical Reports

Method for the Analysis of Tea Aroma by using Solvent-assisted Flavor Evaporation Apparatus

Yuzo Mizukami, Yuichi Yamaguchi

2010 Volume 2010 Issue 110 Pages 110_105-110_112
Published: December 31, 2010
Released on J-STAGE: January 09, 2013

DOIhttps://doi.org/10.5979/cha.2010.110_105

JOURNAL FREE ACCESS

Show abstractHide abstract

We established the method for analysis of tea aroma by using solvent-assisted flavor evaporation apparatus. The solvent dichloromethane (300 mL) is spiked with ethyl decanoate as an internal standard before extraction. The mixture of tea powder (20g) and saturated water with sodium chloride (400 mL) are refluxed at 45 °C for 30 min in triplicate with the dichloromethane (100mL each time). The solvent extract is dried over anhydrous sodium sulfate, and then the solvent is removed by Snyder column to obtain approximately 20 mL. The glass wool (2 g) is inserted to SAFE apparatus for removing interferes, before distillation by using SAFE apparatus (30 °C, 10³ Pa). Thedistillate is further concentrated to approximately 0.2 mL by Snyder column and nitrogen stream before the injection to the gas chromatography.

View full abstract

Download PDF (876K)

Note

Articles at Annual Conference, October, 2010

Editorial Board for Tea Research Jaournal

2010 Volume 2010 Issue 110 Pages 110_113-110_115
Published: December 31, 2010
Released on J-STAGE: January 09, 2013

DOIhttps://doi.org/10.5979/cha.2010.110_113

JOURNAL FREE ACCESS

Download PDF (586K)

Register with J-STAGE for free!