Conyza spp. are troublesome turf weeds particularly in cool seasons because of their rosettes. Characteristics of emergence and seedling establishment of C. canadensis and C. sumatrensis in turf were determined in 1999 and 2000 at the Uji Country Club in Kyoto, with reference to seed dispersal time and turf conditions. Fully mature seeds of the two species were collected twice from populations in a waste area at the site, in mid-August and in mid-September, and sown within 22 days thereafter to the Zoysia turf (cut at 12mm) on a research green and adjacent bare ground. Germination rate of the seeds were as high as 74 to 98%. Little difference was found between C. canadensis and C. sumatrensis for all the characteristics measured. Emergence of summer-sown seeds in turf started later and final emergence rates were lower than on bare ground in both two years. These tendency were more prominent in 1999 because of the better turfgrass growth and drier thatch conditions due to summer rainfall pattern. Emergence rates of autumn-sown seeds in the turf, which were higher than those of summer-sown seeds as a whole, did not significantly differ from those sown on bare ground. Thatch removal in turf completely eliminated seedling death in both species that occurred in untreated turf, suggesting that the time of thatch removal in important for turfgrass weed management. Overwinter plants in turf mostly died in following summer before reaching to the reproductive stage.

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The use of the zoysiagrasses in Saudi Arabia is still limited to Zoysia tenuifolia, which is commercially called as Japanese grass or Korean grass in Saudi Arabia and used as an ornamental purpose only. Several newly developed cultivars of zoysiagrass have been tested in the field located near the Arabian Gulf with bermudagrass and some native grasses. The trial field was set in Khal ji, Saudi Arabia. The entry includes, zoysiagrass (hybrid type) cv. Miyako, Nagisa, Zoysia matrella (CM-22), Aeluropus lagopoides, local and imported bermudagrasses. The F₂ population of Miyako (hybrid type of Z. japonica and Z. matrella) was also tested side by side. All trials were conducted between 1998 and 1999. Miyako and other zoysiagrasses showed sufficiently good performance as compared to others. Among 184 accessions of F₂ generation of Miyako, wide variation was observed and some accessions could be applicable to climatic condition of Saudi Arabia. The present study showed the potential of the use of the zoysiagrasses in Saudi Arabia.

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Unknown Noctuidae moth was captured from several golf courses in the west district of Shizuoka prefecture. This moth was identified Spodoptera cilium Guenée. The external morphology of S. cilium was similar to S. depravata. Moth of S. cilium possessed gray fore wings with small white spot. Larvae of S. cilium possessed darker crescent spot each segment of dorsal aspect of abdomen. Head capsule of 1st instar larvae of S. cilium was black, however S. depravata has light brown head capsule. Developmental rate of S. cilium was shorter than that of S. depravata under 25°C, 16L: 8D condition. S. cilium can eat and grow to feed Cynodon dactylon that S. depravata is impossible to feed. These results indicated S. cilium would be made serious damage to turfgrass of golf courses.

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Effect of bispyribac-sodium on heading and seed production of annual bluegrass (Poa annua L.) was investigated by a pot test under greenhouse conditions and a petri-dish test. Total number of panicles/pot, length of apical node of panicle, total dry weight of seeds/pot, total number of seeds/pot, thousand grain weight and germination rate of seed were significantly reduced at 0.1 and/or 0.3 g a.i./a of bispyribac-sodium. The inhibitory effect of bispyribac-sodium was more remarkable when applied just after heading of the weed than applied at the 3-leaf stage.

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Recently, tremendous interests and expectations on turf playground are growing nationally among the educators, landscapers and general citizen because of environmental and educational benefits of turfgrass. However, establishing and sustaining the turf playground is not easily accomplished due to several reasons including the limited land availability, heavy traffic, financial difficulty and a luck of turf management culture, etc. In this study, turf management program of both public schools and private schools in central Arkansas, USA was investi-gated using the questionnaires in addition to oral interviews. Central Arkansas was chosen for investigation because the climatic conditions such as average temperature and turfgrass species used are relatively similar to those of western Japan. The purpose of this study was to learn about the school turf management system in the United States, which could be helpful for designing the sustainable turf playgrounds in Japan.

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