The germinability of the seed of zoysia grasses (Zoysia japonnica, Z, matrella) shows some characteristics of wild grasses, while it shows a fairly great individual variations. These studies have been made in order to see if their seeds retain the nature of the wild grasses of germinating sporadically over a long period of time, and also to know their length of life. The followings are the results.
1) The seeds have a fairly long life in the case of ordinary dry storage. They still have enough germinability even after 16 years. The germination percentage is low at the beginning, and suddenly goes up in the 2nd year. After the 2nd year it gradually goes up until 7-10th year. The highest percentage exceeds 50 per cent. Then it begins to go down. This shows that their germinability is sporadical over a long period. How the number of days needed for the first seed to start germinating change with years is not clear, but the trend is generally the same as the above.
2) Treatment for the germination: Physical methods do not seem to be effective while a few chemical ones are found quite effective.
3) Keeping of the seeds: They can be kept in the best condition in a desicator. The alcoholic treatment for the selection of ripening seeds does not seem to affect the germination.
4) The seeds complete the suction in 3 or 4 days at the latest. The stored seeds show the decrease of weight (of moisture) of 90 to 95%, while those left alone show the decrease of 100-104%. Those kept in a refrigerator show 98 to 100% decrease after one year, and after that exceed 100%. These percentages are considered to have some relationship with the length of life.

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Although Z, japonica and Z, matrella are short day plants, japonica and one group of matrella flower once a year (spring to early summer), but the other group of matrella flowers twice a year (fall and spring) . Core samples of japonica and matrella cv. Koraishiba were taken from the field at ten days interval and transfered into the growth room controlled at 25 ± 1.5°C and 16 hr daylength. Flowering and vegetative growth were investigated. And also the apexes of upright stems were collected from plants in the field for the histological invest lgat ions. We observed that the flower buds of japonica and both groups of matrella were initiated during early summer to late fall, and deduced that the strain induced during late summer to late fall produced inflorescences twice a year, but that those induced during middle to late fall only in spring. This seemed to result from the difference in the sensitivity for short daylength and temperature.

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Aseptic culture of upright stems of Z, matrella cv. Koraishiba in White's cultural solutions under continuous illumination showed that floral buds were initiated in conditions of low intensity light and low nitrogen concentration. Vegetative growth was correlated with nitrogen concentration rather than light intensity. We considered that the suppressing of vegetative growth due to low nitrogen concentration and some accumulation of carbohydrate conducted to floral buds initiation.

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Manillagrass (K), Japanese lawngrass (J), and Bermudagrass (B) are all summer type turfgrasses used commonly in warm regions of Japan. To compare sensitivity to soil moisture and solar radiation regimes, sod materials of these grass species were each grown under three levels of underground water level and solar radiation (Fig. 1, Tables 1, 2, 5) .
The experiments consisted of two parts, springsummer and summer-autumn-tests in 1983. In the former test, the effects of underground water levels on aboveground yields were examined by two cuttings——1st (July 25) and 2nd (August 30) . The effects of solar radiation on aboveground yields were examined in the latter test also by two cuttings—3rd (September 27) and 4th (December 2) . Dry weight of regenerated aboveground organs was measured throughout 4 cuttings. In addition to this, plant height and dry weight of the residual stocks (including the basal part of stems, rhizomes and roots) were measured in the 3rd and 4th cuttings, respectively.
Responses of each species to the underground water levels were clearly shown in the summertest (2nd cut.) rather than the spring (1st cut.) by way of the decrease in dry weight with increasing water levels. A significant interaction between grass species and water levels in variance analysis indicated that the sensitivity to the water levels differed with the species in the order of B>>J>K (Tables 3, 4) .
Responses of each species to the solar radiation were clearly shown also in the summer-test (3rd cut.) by both the increase in plant height and decrease in dry weight in relation to the reduction of solar radiations. Sensitivity to solar radiation, as a significant interaction between grass species and solar radiation shows, also differed with the species in the order of B>>J>K (Tables 6, 7, 8) .
Dry weight of the residual stocks (exclusive of roots) decreased conspicuously with the reduction of solar radiation. Sensitivity of this part to solar radiation measured in terms of reducing dry weight also differed with species showing a tendency of K>J>B (Tables 9, 10) . This suggests that the growth of each species in the following year may be restricted in the same order describedabove.
From the results mentioned above, the present authors considered that the Japanese lawngrass possesses both plasticity and constancy (nonplasticity) to some extent in response to soil moisture and solar radiation. Consequently, the species appears to be more convenient to practical use than the other two, at least under poor intensive management.

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The effects of SAP (bensulide) on cncroachment of annual pluegrass (Poa annua) and on color, and root depth of a‘Peuncross’creeping bentrass (Agrostis palustris) putting green turf were gmeasured. Herbicides tested during the 3 year period were: SAP EC (0, 0-diisopropyl phosp-horodithioate S-ester with N- (2-mercaptoethyl) -benzensulfonamide) applied at 1.5 g/m² in summer annually and 1.5 g/m² applied in May plus 1.5 g/m² in summer for an annual total 3.0 g/m² and 1.0 g/m² applied in summer plus 0.5 g/m² in May, 0.5 g/m² in June or July and 0.5 g/m² in October for an annual total of 2.5 g/m².
Significant reductions in annual bluegrass populations were recorded from applications and repeated application of SAP, but differences were not significant.
None of the treatments significantly reduced rooting depth.

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1. Pendimethalin [N- (1-ethylpropyl) -2, 6-dinitro-3, 4-xylidine] was very effective for gramineous weed control, but not so good for broad-leaved weed control in pre-emergence treatment.
2. The combinations of pendimethalin and triazine herbicides were very effective for controling many gramineous and broad-leaved weeds and they also controled the considerably developed weeds.
Pendimethalin plus simazine [2-chloro-4, 6-bis (ethylamino) -1, 3, 5-triazine] (150g a, i. + 60g a.i. / 10a) controled the weeds at 0-1.5 leaf stage and pendimethalin plus atrazine [2-chloro-4-ethylami-no-6-isopropylamino-1, 3, 5-triazine] (150g a, i. + 60g a, i. /10a) controled weeds at 0-2.5 leaf stage.
3. The soil treatment layer of pendimethalin was not increased by adding simazine but the layer of pendimethalin was considerably increased by adding atrazine.
4. The phytotoxicities of the combination of pendimethalin and simazine to Japanese lawn grass and Manilla grass were a lithe. But the combination of pendimethalin and atrazine to these lawn grasses were somewhat toxic, especially autumn application of the combination at high dosage was more toxic to Japanese lawn grass then to Manilla grass.

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1. Aqua-Gro^R, a soil permeation agent, promoted the mobility of herbicides, such as simazine [2-chloro-4, 6-bis (ethylamino) -s-triazine], benef in [N-butyl-N-ethyl-α, α, α-trichloro-2, 6-dinitro-p-toluidine], pendimethalin [ N- (1-ethylpropyl) -3, 4-dimethyl-2, 6-dinitrobenzenamine], butamifos [O-ethyl-O-) 6-nitro-m-tolyl) sec-butylphosphoramid-othioate], amiprophos-methyl [O-methyl-O- (2-nitro-P-tolyl) isopropylphosphoramidothioate], benslide [O, O-diisoprpyl-S- (2-phenylsulf onylam-inoethyl) phosphorodithioate], methyl-dymrone [1- (α, α- dimethylbenzyl) - 3-methyl-3-phenylur-ea], and napropamide [N, N-diethyl-2- (1-naphth-yloxy) propionamide] in soil.
2. In the case of simazine, the increase in downward permeation in soil was proportional to the amount of Aqua-Gro^R added, regardless of rainfall.
3. Addition of Aqua-Gro^R to an emulsion of simazine resulted not only in an increased mobility of the herbicide but also in redused adsorption by soil, i. e., the herbicide was less readily retained by soil.
4. In the model experiments on soil adsorption and water solubility of simazine, it was found that Aqua-Gro^R decreased the adsorption to less than 30% and increased the solubility by 100%.

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1. Zoysia spring dead spot which occurred in our field showed restrainning effect by the anti-Rhizoctonia fungicides.
Rhizoctonia sp, is separated preferentially from this disease.
The symptom of this disease is similar to other disease by Rhizoctonia solani.
Then it was confirmed whether or not Rhizoctonia sp, which is separated from this disease possesses the pathogenicity to the turfgrass by the artificial infection method.
Also, it was tested whether or not Rhizoctonia sp, which is separated from the provisional name of Koraisiba Rhizoctonia hagarebyo (Zoysia Rhizoctonia leaf spot) and Bentgrass okkasyoku patch (Bentgrass yellowish brown patch) in Japanese name posseses the pathogenicity to each turfgrass.
2. Rhizoctonia sp. which is separated from Zoysia spring dead spot showed the pathogenicicity to Zoysia-grass and Bentgrass.
3. Rhizoctonia sp., also, which is separated from the provisional name of Koraisiba Rhizoctonia hagarebyo and Bentgrass okkasyoku patch showed the pathogenicity to each turfgrass.
4. Aboue-mentioned, 1 want to give the name of Zoysia Rhizoctonia spring dead spot (Koraisiba Rhizoctonia haruhagebyo in Japanese name) and Koraisiba Rhizoctonia hagarebyo (yellow patch in English name) to Zoysia spring dead spot and the provisional name of Koraisiba Rhizoctonia hagarebyo respectiuely.
About the name of the asssumed of Bentgrass Yellowish brown patch is required still more consideration.

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Electron microscope observations were carried out for the leaves and shoots from zoysia grass (Zoysia tenui folia Willd, ex Thiele) showing symptoms of leaf chlolosis in association with stunting and witches-broom growth of shoots. In all samples examined, a large number of polymorphous bodies were detected consistently in the siebe tubes and occasionally in the phloem-parenchyma cells. The most abundant bodies were nearly round, 100 to 250 mμ in diameter, and contained ribosome-like granules and fibrous materials corresponding to nuclear net-strands. Budding-like protrusion and constriction of large bodies were also observed. The presence of these structures suggests that leaf chlolosis and abnormarity in growth of zoysia plants mentioned above may be caused by mycoplasma-like organism, and a new name “yellow dwarf” is proposed for this disease. In chlorotic leaves, cessation of lamella structures at the beginning of chloroplast development and destruction of immature chloroplasts were suggested to be the cause of chlorosis.

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In 1983, the search for seasonal prevalence of occurrence of Japanese beetle, Popillia japonica NEWMAN, was conducted by You-in trap cotaining lures on nineteen golf courses in Japan. A summary of the rerults is shown bellow. The areas with a very severe occurrence of adults were the golf courses in Tohoku, Shinshu and Tokai districts; however, Chugoku, Shikoku and Kyushu countrys were a light occurrence. Furthermore our experiments clearly demonstrated that the time of adult occurrence was closely connected with the mean temperture of each golf course. This trap could also utilize for the forecasting of adult occurrence and an index number of control with pesticides. Judging from number of catches of beetles per a trap during the summer season were above 3000, the use of many traps and chemical insecticides may be possible to decrease the beetle population.

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