In January 1953, it was not so cold, and the winter buds commenced to grow up gradually, so we feared if they should be suffered from sudden severe cold. Taking this chance, we tried to examine if there existed any varietal difference in cold resistance of the tea buds.
The branches of each variety with buds were gathered from the field in winter and spring, and part of them was tested the refractive index of the cell sap, and the rest was put into a refrigerator which was regulated at -5°C. After 1-, 3-, or 5-hours' treatment, they were put out and the, cold injury was examined. The varietal difference was evident which was positively correlated with the refractive index. Miyoshi was weakest and U-21 (triploid) and Yamatomidori were strongest.
As the buds began to flush in spring, the refractive index and the cold resistance were gradually decreased, and the order of cold resistance among varieties was varied. This alteration seemed to be caused. by the varietal difference of activity of spring buds.
In winter field, it was observed that nearly 20% of tea. buds were killed after severe cold attack, and so, it might be thought important to avoid non-winter-hardy varieties in such a district.

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Some experiments were carried out if the cold resistance of the tea varieties could be tested by measuring the plasmolytic.permeability of the tea leaf cells, and the following results were obtained.
1. The tea varieties which were more resistant to cold showed more permeable of the cell membrane for water and solute and needed shorter time for deplasmolysis of the cells.
2. The deplasmolysis time was shorter in the triploid plants which showed higher cold resistance in spite of their lower osmotic pressure than the diploid ones.
3. It was practically useful that the cold resistance of any tea variety could be judged under the same treating solution and time as in the case of Yabukita.
4. It was recognized that this method was available to judge the cold resistance of the tea varieties.

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1. Pinellia ternata BREIT is a perennial plant, and as far as its corm is killed, the resuscitative faculty cannot be deprived. The controlling power of Degrass, 2, 4-D (amine)' As₂O₃, P.M.C., NH₄SCN was more effective on the top of the grass than that of 2, 4-D (Na-salt). The destroying rate of the corm by spraying with 2, 4-D (amine) of 11 kg. per tan was 53.33%, but this concentration exceeded an economical limit.
2. The influence of various weed killers on the tea plant of four years old by cutting was as follows: 2, 4-D (Na-salt) and M.C.P. were very powerful, NH₄SCN and XL 283 were powerful, but chlorate soda, Degrass, As₂O₃, and Weedone crab grass killer were not, by spraying with these chemicals of 1.1 kg. per tan.
3. The harmful effect of Degrass on the young tea plant was very strong, for 30% of the plant was killed even when the chemicals were sprayed with the concentration of 2.1 kg. per tan.
4. The residual effect of these weed killers on radish was investigated by examining germinating rate, length of stem and root, and fresh weight of sprout. 2, 4-D (Na-salt) and M.C.P. were very injurious, XL 283 was injurious, chlorate soda, Degrass, D.K., NH₄-SCN, As₂O₃, phenyl mercuric chloride, KCIO₃, phenyl mercuric acetate and Weedone crab grass killer were slightly injurious.

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1. The yield of tea leaves was influenced by a slight variation of the plucking time, so, it does not show the correct value unless it is adjusted.
2. The yield was observed that it was closely correlated with the maturity (indicated by the ratio of bhanji shoot) and the number of shoots by a uniformity trial of sampling on the tea garden of the variety "Tamamidori".
3. The observed values of dry and fresh yield were adjusted by the maturity and number of shoots, both at mean and at the presumed best plucking time, as well as the effect of adjustment was tested by the reduction of variance or coefficient of variation of the sample.
4. The adjustment by the multiple regression of maturity and number of shoots proved more effective than by the single regression of each. The reduction of coefficient of variation by the adjustment is shown in the following table.
From the result, the adjustment by the number of shoots was more effective, compared with each of the single regressions. However, some kinds of experiments may need not any adjustment by the number of shoots, or may need by other factors, but no case would be expected in which the yield would not be adjusted by the maturity
5. The estimated yield with its confidence limits at the presumed 'best plucking time was calculated, and this figure would be recognized the most reasonable value in this sample.

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1. Further survey of the japanese brown tail moth (Euproctis pseudoconspersa STRAND) was made concerning the larval moulting of the first generation. From the results of this survey together with the first report, it was found that the larvae had five-seven moultings but some of them might have eight moultings as they did in the second generation.
2. The total life-cycle from larva to adult took 53-61 days at 25°C., and 75% R.H. This period was one month or 12-20 days shorter than that of the first or second generation in the natural environment.
3. The number of eggs containing in the abdomen of 60 female moths was counted, one female had 373.5 eggs on an average and 454 in maximum which was much larger than that of laid eggs.
The number of the residual eggs in the abdomen of 10 females after laying eggs was 81.3 on an average, 292 in maximum, and 58 in minimum.
4. The number of eggs containing in eggmasses collected in the field was as follows:
5. In Japan (Kanaya), they repeated two generations a year, the larvae had five-eight moultings, and the male moths had two seasonal color forms, one was black and the other yellow as female. The former appeared in the first generation, and the latter in the second.
In Formosa (Taipei), they had five generations a year, the larvae had usually five moultings, the black moths appeared in summer' the yellow in winter, and the intermediate in April.
6. Two species of Hymenopterous egg parasites were found in Japan, one was Telenomvs sp. (Scelionidae) and the other Trichogramma dendrolimi MATSUMURA. The percent parasitization by the former species was 38.4% in the first generation, and 8.7% in the second in 1953, while that of the latter was 0.3% in the first and 0.5% in the second respectively.
The former species was one of the most important natural enemy on Evproctis pseudoconspersa whose host was recorded as only one. The latter was not so effective enemy on Evproctis pseudoconspersa, however, seventeen other hosts were found and was a very effective parasite on the tea tortrix (Adoxophyes privatana WALKER, Homona coffearia NIETNER) and Phrixolepia serieea BUTLER (Coehlidionidae).

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We examined some problems about the control.of the small tea tortrix by parathion.
1.Parathion was more effective than the other organic phosphorous insecticides.
2.The best result was obtained in controlling it, when 0.04-0.02% parathion was used at the rate of 160-230 gallons per acre.
Parathion emulsion and wettable powder were nearly equal in effectiveness to control the small tea tortrix, and parathion dusting seemed not to be so effective as spraying.
3.Parathion emulsion mixed with Bordeaux mixture (0.4%, ) or Zineb (1/50C) was so effective for controlling the small tea tortrix.

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1. The tea red spider (Tetranychus japonicvs HOTTA) is the most common pest of the tea plant in Japan, and during the spring months, it is found in great number, causing much damage. In this paper, an account of its population density and life-history in the field is given.
2. From April 1952 to March 1953, the tea leaves were sampled every five days, and the number of spider was counted separately on every stage.
3. During one year, there occurred two peaks of population density, one in spring and the. other in autumn. In the former season, it was higher than in the latter.
4. The period of total life-cycle observed in the field was different from that in the laboratory and in the former case, it had no correlation with the air temperature.

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The relation between the electric specific conductivity of tea infusion and its quality (taste) was tested by the same method as used in the case of leaf tobacco.
The result of the experiment indicated that a high correlation coefficient existed between the specific conductivity of infusion and its concentration or quality (taste) of tea. So, the authors are expecting that this method may be available for scientific estimation of the quality of tea.

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1. The tea leaves of the varieties of Yabukita (for green tea) and Benihomare (for black tea) were collected from Kagoshima, Shizuoka and Saitama prefectures on the first, second and third plucking seasons during the three years from 1949 to 1951, and the regional variations of the chemical constituents of the leaves as well as the hot hydrochloric acid soluble components of the garden soil on which the sample plants were grown were researched.
2. The analyzed constituents contained total-N, soluble-N, caffeine, tannin, hot water extract, crude fiber, crude ash, and alkalinity of ash. From the above-mentioned data, insoluble-N, caffeine-free soluble-N, the ratios of N-Fractions with each other, the ratios of soluble-N or tannin in the hot water extract were calculated.
3. The analysis of variance of the chemical constituents showed the following significant level of F value on the principal sources of variation which were the year, the variety, the locality, and the season.
4. As for the annual variation, soluble-N. caffeine, crude fiber, and crude ash were most abundant in 1950 and least in 1951, while tannin and alkalinity of ash showed the opposite tendency. And total-N, insoluble-N, caffeine-free soluble-N were least in 1949.
The annual variation was considered to be affected by the climatic factors, but a decisive relation between the annual variation of the chemical constituents of the tea leaves and the climatic data could not be obtained, so far as this survey concerned.
5. On the varietal difference, Yabukita contained more insoluble fraction of the nitrogenous contsituents while Benihomare contained more soluble part. The ratio of these fractions to the total-N showed the same tendency. It was favorable that the ratio of caffeine-free soluble-N to total soluble-N or that to hot water extract was higher in the Yabukita variety for the green tea, but the content of caffeine-free soluble-N and its ratio to hot water extract of this variety were remarkably reduced in the summer crop than the spring one, and this fact explained the deterioration of the qualities of tea made with Yabukita in summer. And it was also reasonable that Benihomare for black tea contained more tannin and hot water extract and showed higher ratio of tannin/riot-water-extract.
6. The local variation which was the main purpose of this research brought about the following results.
i) The content of ash and its alkalinity of the tea leaves indicated the most significant difference which was due to the soil components.
ii) All nitrogenous constituents except caffeine and the ratios of N fractions with each other showed no significantt difference. This result seems to be favorable for increasing the excellent tea variety for green tea in every tea-producing district, as many analytical data bad shown the fact that the more the total-N, the better the quality of tea.
iii) The tea leaves of the Kagoshima product was characterized by much crude fiber, and less crude ash and alkalinity. The ratio off tannin/hot-water-extract was much larger than the other two places. The local difference of the ratio was low in the spring crop but became higher in the summer crop, especially in the second season when the ratio was higher as the latitude of the producing district was lowered, so, it was recognized that the black tea production was advantageous in the southern region in Japan.
iv) The Saitama product had the opposite characters to the Kagoshima one, with little fiber and much ash, eapecially in the summer.
The soil of Saitama tea garden was very abundant in phosphoric acid and manganese. But the relation between soil components and ash of tea leaves or its alkalinity was proved significant only in the cases of soil iron-leaf ash and soil alumina-alkalinity of leaf ash with correlation coefficients of +0.903 and +0.960 respectively.

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The nephelometric method for estimating tea catechins in the tea leaves reported by Oshima and Nakabayashi wass modified by substituting the standard for D-catechin solution. (100mg./100cc), and a conversion table obtained by this new method was shown in Table 2.

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As YODER'S method was not available to analyze the soil aggregate of the Makinohara diluvial upland soils, the method was modified as follows :
The dry sieving apparatus has 2 sieves (6 and 2.5mm.), and the wet sieving apparatus consists of 4 sets of 4 sieves (2, 1. 0.5 and 0.1 mm.), the latter is operated for 60 min., with 6 cm. of amplitude and 20 reciprocations per min.
By above-mentioned method, the aggregate was analyzed of the Makinohara brown soil and "Kuroboku" sampled from an uncultivated land as well as from a tea garden.
The soil mass and the soil aggregate were perfectly separated and determined by wet sieving of the residual finer part after dry sieving of 2.5 mm.
The aggregate thus determined was water-stable and indicated the physical structure of the Makinohara diluvial soils clearly.

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