In order to obtain fundamental data in classifying and breeding or growing Japanese lawn grasses, which are most commonly grown in parks, golf courses and athletic fields in Japan, and found wild in most parts of the country, the authors investigated the external and internal structures of one of the typical Japanese lawn grasses, Zoysia japonica Steud. I. Anatomy of leaves.
1. Because of a striking development of Y-shaped moter cells in the leaves opened toward the upper surface of leaves, leaves of grass roll inside easily when withered. This keeps leaves from heat injury or drought as the more stomata are distributed over the thin, upper surface of leaves than lower ones. Occurring more stomata on the upper side of leaves are suggested also favourable in applying macro or micro-element-fertilizers over leaves.
2. As the cuticular thick-walled cells are well-developed in the epidermis and around the vascular bundles, the leaves of grass are strongly resistant to the external forces, such as tamping or scuffing.
II. Anatomy and development of stems.
1. Well-developed thick-walled mechanical structure seen particularly in the epidermis of erect stems, in the endodermis and around the vascular bundles of stolons increase wear resistance against twisting or friction of stems.
2. New erect stems originated from neartop nodes of stolons, inclined toward growing direction of stolons in the case of mowing lawn always to one-way direction. Sloping land, or scuffing limited to one-way direction in the putting-green in golf courses often form so-called “lawn grass bud” (refers to stolons spreading to one-direction) producing a little resistance in putting golf balls.
3. It was shown that only two primary erect stems are always produced from a node group of stolons that consists of three nodes each, occurring very close together and having two definite buds.
4. Adventitious buds will be given off 8-12 contracted nodes at the base of erect stems and can give rise to several secondary erect stems depending on the growing conditions. From these facts in making lawn fine and well-thicked, managements, such as top dressing, mowing, moderate tamping and fertilizing are important to encourage the formation of adventitious buds.
5. Stolons are formed, in other words, changed from erect stems during the course of growth, not from the branching of the stolons. This evidenced from the facts that the erect stems consists of “groups of one node”, but stolons are always composed of groups of three nodes that occur very close together.
6. On the stolons many erect stems are produced and at the base of each erect stem the secondary new erect stem are formed. These new stems offen change to stolons as affected by stimulation, such as tamping. To promote this“transformation”of lawn grass is considered to be one of the important factors for making new thick-covered lawns quickly with few materials.
7. Repeating lawn mowing very often resulted in a poor growth and a reduction of yield per year.
8. In winter Japanese lawn grass turns brown, but a growing point of grass in a sheath of erect stems is are covered with died leaves, scales and bracts and it is kept from cold. In spring, however, the greening of lawn is retarded by the presence of the died brownish leaves, causing also thin growth of new shoots. To prevent these, lawn burning made as early as possible in spring after heavy cold season passes will be helpful for encouraging the growth of grass.
III. Anatomy of root.
1. Rooting of stolons occurs at each node: three to four roots are produced from a node group of stolons, that is, two roots arising from the first and the second nodes and one or two roots from the second or the third ones counting from the stolon base.

View full abstract

We made an experiment in order to decide the effects of scattering quantity and interval. The growth control matter (EL 500) were studied in cool season turfgrasses, and following results were obtained.
1. Control effects
The control effects were notable, especially in the solid matter.
2. Control interval
Both solid matter and liquid matter, control effects had continued about two months. But two months later, it was gone.
3. Damage from agricultural chemicals Liquid matter had no damage from agricultural chemicals.
Solid matter had damage from agricultural chemicals, but it was a little.

View full abstract

Dollar sopt disease in Japan was first reported in 1965 as a minor disease of bentgrass, but has now became one of the serious diseases on putting greens of golf courses. In this study, several isolates of the causal pathogen Sclerotinia homoeocarpa from Kagawa, Hyogo and Shizuoka were subjected to the tests of pathogenicity and cultural behaviors.
(1) Inoculation tests with five isolates on creeping bentgrass (cv. penncross) sods in the pots revealed that the disease occurred at 10°C and became severer as the rise of incubation temperature. At 25 and 30°C, the turf was completely withered within 3 days after inoculation.
(2) Host range of the pathogen was determined by inoculation with two isolates on 12 gramineous plants grown on the pots. All of the grasses shown below were heavily attacked at 25°C.
Seedlings: Creeping bentgrass (cv. seaside), Italian ryegrass, Kentucky bluegrass, Perenial ryegrass, Tall fescue, Japanese lawngrass, Bahiagrass, Centipedegrass, Weeping lovegrass Adult plants: Creeping bentgrass (cv. penncross ), Italian ryegrass, Tall fescue, Manila grass, Japanese lawngrass, Bahia grass, Bermudagrass, Weeping lovegrass
(3) Behaviors of mycelial growth of five isolates were compared on 6 cultural agar media. There was no significant differences among isolates in the growth and coloration of submerged mycelia. All isolates produced only sporiferous structure. Mycelial growth on PDA was evident in the range of 5 and 35°C and was maximum at 20-30°C. It was suggested that the strains of the pathogen found in Japan resemble the major strain distributed in USA and Australia.

View full abstract

Dollar spot disease caused by Sclerotinia homoeocarpa is recently recognized in Japan as one of the serious diseases of bentgrass putting greens in golf courses. This study was conducted to survey fungicides which could efficiently control the diseases and low in fish toxicity. The results obtained are summarized as follows:
(1) Based on the experiments of antifungal activity to 5 isolates of the pathogen on PDA, iprodione, procymidone and vinclozolin were found to be a potent active chemicals (ED₅₀ less than 1 ppm) with low fish toxicity (TLm 48 more than 10 ppm) .
(2) These three chemicals completely controlled the disease development on penncross bentgrass sods grown in pods at 25°C by single application before inoculation with 3 isolates obtained from different districts.
(3) Field investigations on penncross bentgrass turf in spring and summer seasons demonstrated that the dollar spot patches disppeared by single application at doses 0.25 and 0.5g/m² of procymidone and vinclozolin. The application of iprodione at 0.23g/m², however, seemed to be effective only when it was applied before or at the early stage of disease development.

View full abstract

1. This report was carried out to investigate the Vicissitude of number of the fungi isolated from Rhizoctonia Large Patch after treating with the fungicides, and, to experiment the relationship between the permiability of the fungicides, the volume of diluted solution and the spreader, and, the differeuce of the fungicidal effect with the same volume of diluted solution on the different managementing turf.
2. After each fungicide was treated with the customary diluted solution on the lesion in autumn, the fungi were isolated at intervals from the part of leaf and stem (the clipping surface to the depth of 1.5cm) untill spring.
So that, the number of the fungi, which each fungicide was treated on, decreased extremely at the day, but not disappeared. After the decreasing situation was continued in a definite period of time, the number of the fungi increased again.
The period of the decreasing situation of tolclofosmethyl was continued above 16 weeks, and, TPN, mepronil and iprodione were contin ued from 4 to 8 weeks.
In case of the treatment with each fungicide at 2 times of the customary volume, the number of the fungi of tolclofosmethyl, TPN and mepronil decreased more than tho customary volume at the day.
The period of the decreasing situation was continued longer than the customary volume among the fungicides. And the fungi dis appeared among the fungicides. After that, the fungi increased again as the same number as the custimary volume.
But the number of the fungi and the period of decreasing si tuation with iprodione were the same as the customary volume.
After each fungicide was treated on the disease, the effect appeared at 3 hour later.
3. In order to see the vicissitude of number of the fungi in the runner (the depth of 1.5 to 3.5cm), the fungi were investigated after the customary diluted solution of tolclofosmethyl at 1 time and TPN at 2 times in intervals of 2 weeks were treated respectively.
So that, the fungi were isolated from the plot of each fungicide as the same number as the plot of no-treatment in all nerind.
4. In order to see the permiability of the fungicides, the fungi were isolated from the runner and the root (the depth of 3.5 to 5.5cm) after a certain volume of the customary diluted solution of tolclofosmethyl and TPN was treated.
So that, the fungi with 8 times of the customary volume of each fungicide were the same number as half of no-treatment in the runner.
The fungi in the root disappeared with 4 times of tolclofosmethyl and 8 times of TPN respectively.
To compare the permiability, the solution of tolclofosmethyl, which the osmotic and the customary spreader were added to, was treated on the leision.
So that, the fungi in runner, which were isolated from the plot of the osmotic and the cust omary spreader respectively, were the same number.
5. After the equal volume of the solution of tolclofosmethyl was treated on the lesion of green and fair-way respectively, the fungi were isolated from the part of the runner.
So that, the number of the fungi on fair-way was more than on green at 2 times of the customary volume.
And the treatment with 2 times (2g/2l/m²) of the customary volume of the solution was more effective than with 2 times (2g/l/m²) of only the dosage.

View full abstract

Soil adsorption of insecticides was tested, when the mixture of soil conditioners and sand was used as bed soil.
84% MEP treated on soil was adsorbed in case of the mixture of humus material mainly containig humic acids and sand, however, less than 20% treated MEP was adsorbed in the case of only sand.
Perlite and vermiculite didn't increase soil adsorption of insecticide compared to only sand. Tested what kind of factor effected the amount of adsorption of MEP, it was dependent on both the rate of treaaed MEP and the rate of humusmaterial in the soil.
Both high rate of treated MEP and the mixed soil containig humus highly increased the amount of adsorption of insecticide.
A large amount of watering after treated diazinon brought diazinon to deeper soil area.
Also, addition of soil penetrative material, AQUA-GRO to diazinon got the same result. This test suggested that soil adsorption of insecticides might be caused by the physical bond between soil and insecticide.

View full abstract