Deposition and behavior of simazine and pendimethalin treated on the leaves of Manilagrass (Zoysia matrella) was studied in 1990. In the test in early April, simazine and pendimethalin were applied 2 kg/ha (as a.i.) to the dormant turf field, and in late October, these herbicides were applied with the same dosage to the growing turf field mowed at 25 mm or 50 mm height, respectively.
The amounts of the herbicides deposited on the turf leaves were influenced by the formulation type, spray volume, SAA addition, and the plant height. The initial amounts of both herbicides detected from the leaves after treatment were high when the herbicides applied with low volume spray of wettable powders, and added SAA to the water solution. In addition, the both herbicides, deposited higher concentration on the leaves mowed at 50 mm height than at 25 mm. During the experiments, simazine detected from the leaves remained in higher concentration levels, while pendimethalin decreased rather rapidly.
The behavior of simazine and pendimethalin retained in the turf leaves was studied by the pot test in a green house in 1991. Simazine and pendimethalin were applied 2 kg/ha (as a.i.) to the dormant turfgrass in early April and to the growing turfgrass in mid May. Simazine residue in the leaves decreased a little during the test period. Artificial rainfall applied at an earlier stage slightly promoted run-off of the simazine from leaf surface to the soil.
Pendimethalin residue decreased gradually provably due to the herbicide run-off from leaves to the soil by rainfall and also to the volatilization from the leaf surface.
With the both herbicides, the amounts runoff from the leaves to the soil were greater in the early-April treatment than in the midMay treatment.

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Isolates of Sclerotinia homoeocarpa were collected from bentgrass putting greens where iprodione had failed to control the dollar spot disease. These isolates were highly resistant, as assessed by hyphal growth on fungicideamended PDA, to dicarboximide fungicides and PCNB, showing 300 to 1, 500 times higher in EC₅₀ values as compared with normal isolates. Based on the sensitivity to iprodione, these isolates could be classified into three groups showing MIC values of 4.0-5.0, 200-500, and 1, 000-1, 600 ppm, respectively. All isolates belonging to any group were equally sensitive to benomyl and propiconazole. The use of these two chemicals was quite effective to control the disease development in the inoculation experiments with the iprodioneresistant isolates and creeping bentgrass seedlings.
Successive transfer of the resistant isolates on iprodione-amended and iprodione-free PD A for about one year exhibited that the level of resistance was maintained on the former medium but was gradually reduced on the latter medium.
The use of benomyl alone for the control of the dollar spot disease for one year completely depressed the appearance of iprodione-resistant strains. It was thus suggested that the alternative use of fungicides having different modes of action may effective to suppress the outbreak of resistant strains.

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Experiments were conducted to obtain some basic informations on the quantities of underdrained water and the agricultural chemicals under various intensities of precipitation and overhead irrigation by using test turf-green (Pencross bentgrass) set up in sand dunes of suburban Niigata during 1990. The chemicals used were acephate, iprodione, flutoluanil, oxine-copper, fenitrothion and diazinon. The results obtained were as follows:
1. There were two draining patterns in the rate of underdrainage. When the soil was wet condition, the drained water ran off quickly in large amount after one hour of sprinkler irrigation, then decreased gradually. While under dried soil condition the water drained slowly and the initial drainage was less than those of wet soil.
2. The amount of drained water was determined absolutely by the amount of precipitation in each month than those of sprinkler irrigation.
3. Higher recovery of applied chemicals were found with acephate, followed by iprodione, flutoluanil, oxine-copper and fenitrothion. Oxine-copper and fenitrothion were detected in least. Diazinon was not detected in the drained water.
4. Most chemicals were detected in the drained water within a few weeks of application, especially in three days in case of acephate. Flutoluanil seems to appear in slower rate.

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Pre-emergence herbicidal activities of simazine, propyzamide, pendimethalin and asulam against Digitaria ciliaris L. and Poa annua L. under different soil conditions were determined by the pot tests in a glasshouse. The four herbicides tested were more active in the sterilized than in the nonsterilized soil. Simazine, propyamide and asulam showed stronger activities at 100% water-holding capacity than at 60 %, while pendimethalin was more effective at 60%.
Dissipation of the four herbicides following applications to a turf field of Manilagrass (Zoysia matrella) was studied 1990 through 1991. In general, residues of the herbicides in soil decreased rather rapidly during the first two weeks after application and then dissipated gradually. In particular, more rapid decreases of the residues were observed for the plots applied in spring to early summer, whereas even 5 months after application 5-25 % of applied dosages were found in the plots applied in autumn. Among the herbicides tested, asulam was found to decrease most rapidly regardless to the application time.
Consequently, dissipation of a herbicide in turf field appeared to be affected not only by physico-chemical characteristics of the herbicide but also by climatic conditions which influence biodegradation by promoting or delaying the growth of soil microorganisms, chemical degradation, vaporization, and photolysis.

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Effects of 6- (N-benzyl) aminopurin (BAP) on weight of turfgrass, Lolium perenne L. and chlorophyll content in the plant were studied in a controlled growth chamber.
Absorption and translocation of ¹⁴C-BAP in two turfgrasses, L. perenne L. and Agrostis stolonifera L., were also studied. And the following results were obtained.
Weight of plant of L. Perenne and chlorophyll content in the plant were both increased with the treatments of 6-BAP at 10^-7-10^-5 M. There were quantitative differences in the rate of the absorption and the translocation among two turfgrass species, L. perenne and A. stolonifera.
Thses differences of BAP my cause the differences in the promotive effects of BAP among turfgrass plants.

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