1. This experiment was carried out on the relationship between the occcurrence of Rhizoctonia Large Patch and the vicissitude of number of the fungi isolated from this disease, and the inhabiting range of the causal fungi.
2. The trace of autumn lesion remained during the winter dormant stage of Zoysia turfgrass, and the size and form of the trace continued into the spring lesion as it was. After that, the spring lesion developed larger and larger.
In the latter part of spring the lesion disappeared completly, then in the autumn the lesion started again.
The recovering of new turf in the summer season resulted from not only the healthy turf in contact with the lesion but the remainning turf in the bare area in late spring.
3. In this test, the occurrence of disease in the spring was from the last ten days of March or the first ten days of April to the middle of June, and the most intensive occurrence of the disease was from the middle of April to the middle of May.
In the autumn it occured from the first ten days of October to the last ten days of November.
4. The vicissitude of Rhizoctonia solani considered to cause this disease was approximately the same as the occurrence of this disease, but the fungi in the spring were isolated more frequently than in the autumn.
The number of fungi in creased before the appearence of spring and autumn lesion.
The fungi in the letter part of the spring lesion were hardly isolated at all in spite of the lesion and not complately in the summer.
But the fungi in the latter part of the autumn lesion and the dormant stage of Zoysia turfgrass had a low isolation, and before the appearence of the spring lesion was higher.
5. It's considered that the causal fungi inhabit the surface of turfgrass soil and the hyphae develop into not only the disease turf area but also the healthy turf area that is in contact with it.

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1. This experiment was carried out concerning the outbreak of Rhizoctonia Large Patch by the artificial inoculating method of Rhizoctonia solani into the Zoysia turfgrass and the outbreak conditions of this disease by this artificial inoculating method.
2. When the amounts 5-40g of the soil and wheat bran mixed culture of the causal Rhizoctonia solani isolated from this disease were inoculated to the potted turfgrass (Zoysia matrella) in 15cm diameter, the outbreak of disease was observed with the infection rate of 55-70% after 30 days, but the inoculation rate showed no difference in the results.
3. When the relationship between the outbreak of disease against the Zoysia turfgrass and the watering interval, as the rainy interval, was tested under constant soil moisture and saturated air moisture by the artificial inoculating method, the shorter the watering interval was, the higher the infection rate became.
As the result, it's considered that the outbreak develops largely in because of continual wet turf surface which was maintained by watering during the testing period.
4. The relationship between the outbreak and the removing thatch was tested by the artificial inoculating method, so that, the outbreak rate increased highly when the turf was injured in the processes of removing thatch. The improved environment did not compensate for the injuring to the turf.
5. When the outbreak of disease was tested in the growing turf stage after cutting upper stem and the spring bud stage by the arificial inoculating method, the outbreak in both stages was greatest when the young stem came in contact with the inoculant.
6. The susceptibility of disease was tested in the Zoysia turfgrass by the artificial inoculating method, consequently, the difference of outbreak was as follows (from the most susceptible) Zoysia matrella (broad leaf) >Zoysia matrella (narrow leaf) > Zoysia japonica > Zoysia tenuifolia.

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In my previous papers (1973-1978), it was shown that two types of fairy rings were recognized: the one was Lycoperdon perlatum Pers. which showed green rings on Zoysia spp., and the other was Lepista sordida (Fr.) Singer which showed green and necrotic rings on the Zoysia spp. and the tifgreen. And that the necrotic type of fairy rings on Zoysia mat rella L. was recognized at the golf course. From these necrotic rings, Lepista sordida (Fr.)
Singer is detected at the portion of plant roots area in the soil; and Helminthosporium sp., at the necrotic leaves, stems and roots of the plant. Further experiments and observations were carried out concerning the fairy rings on the trufgrasses. Their results are as follows.
Four types of the fairy ring, caused by the Lycoperdon perlatum Pers. or Lepista sordida (Fr.) Singer on the Zoysia grasses and the bentgrasses, were recognized. The first type is the case of no ring, the second type is the green ring, the third type is the green and necrotic ring, and the forth type is the necrotic ring; and Curvularia sp. was detected at the necrotic leaves and stems of the plant.
These results suggest that the ring of the fairy ring on turfgrasses is not caused directly by the Lycoperdon and Lepista themselves, but caused indirectly by them; namely, these mushrooms present the circumstances to produce the several types of the ring.

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The application of the atrazine mixtures [atrazine (2-chloro-4-ethyl-amino-6-isoprop-ylamino-s-triazine) plus orthobencarb (S- (2-chlorobenzyl) N, N-diethylthiocarbamate) and atrazine plus MCPP (2- (2-methyl-4-chlo roph-enoxy) propionic acid) ] was tested on the turf.
The mixtures were highly effective on broad leaf weeds, such as leguminous weeds, which had been difficult to control by common soilapplied herbicides. The mixtures were effective by either soil application, or foliage application. Foliage application of them were excessively effective for most of weeds, including perenial weeds such as lawn pennywort (Hydroctyle sibthorpioides Lam.), creeping woodsorrel
(Oxalis corniculata L.), paspalum (Pasupalum thunbergii Kunth) and aging annual bluegrass (Poa annua L.), Japanese clover (Kummerouia striata Schindler) . They were more effective on perennial weeds by repeated applications, or by cutting their leaves after application.
The injury to turf grsses was not observed at recommended dosage in field and pot tests.
Therefore, the mixtures were highly effective for many weeds, and showed no injury to turf grasses as Japanese lawn grass (Zoycia japonica Steud.) and manila grass (Zoycia matrella Merr.) .

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To control pests in turf soil, it is important to make insecticides penetrate into soil. Insecticides cannot penetrate by themselves even if they are very abundant. We made some experiments to choose the best chemical to help insecticides penetrate out of over twenty surfactants at home and abroad.
1. Surfactants (0.5%) were added to MEP diluted to 1/500, When TSG-79AG, which was test, wasaadded, the insecticides in Bsoil layer (2cm-4cm) was 13.3 times as much as when nothing was added. When TSG-1402, which was second best, was added, it was 12.6 times. Most surfactants made the rate of penetration higher.
2. The mortality of the third-stage larvae (Anomala schorfeldti Ohaus) kept in B soil layer was only 14.3% ten days after spraying in case of no addition. But it was 93.3% in TSG-1402 spot and 90.0% in TSG79AG spot. So addition of surfactants was very effective.
3. When third-stage larvae were kept in sandy soil spots of MEP of various density, the mortality of the larvae in the sandy soil spots of over 0.6ppm density was 100% ten days after spraying.
4. When we measured penetration into cloth and surface tension of various Kinds of surfactants, TSG-7606 was the highest. TSG-1402, which had the highest penetration, was lower than TSG-7606. It seems that penetration into plants has nothing to do which penetration into soil.
5. When we measured the amount of the insecticide in B soil layer twenty-four hours, forty-eights hours, seventy-two hours after spraying respectively, it increased in order. It seems to gradually move down slowly with water.

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The author made some experiments on the functions of noise reduction by vegetation and ground in a reverberation room, nurseries and fields.
The qualitative results of the investigations are summarized as follows:
The noise reduction by forests are classified according to their functions in two categories; reflection and absorption. It was explained that reflection was more important than absorption for the function of noise reduction. This theory is not the traditional one. The effect of the reflection increased as the density of foliage and the size of the leaves. Therefore, the broad leaved trees were better than the conifers.
The noise was notably reduced according to the reflection by forests at high frequency bands. But by grass fields, it was remarkably reduced at a low frequency of less than 500Hz, and the reason was cosidered that the noise reduction was related to the softness of the top soil, not the species of grass. For that reason, the excess attenuations in decibels by forest become smaller at a frequency between 500 and 2000Hz. But by hedge, they become uniformly larger in proportion as the frequency increases, because the quantity of absorption by ground is too small.
As mentioned above, it was considered that the most appropriate planting design had many hedges each owning foliage until the ground was perpendicular with the couse of sound propagation and kept the top soil soft on the planting site.
On the other hand, plants assist the wind in masking some offensive noises. This masking is not effective against traffic noise, but it is very interesting in acoustical psychology and further quantitative studies are necessary for acoustical control in the exterior environment.

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