日本のゴルフ場におけるツルスズメノカタビラの侵入実態
2002 年 47 巻 2 号 p. 82-88
詳細
2002 年 47 巻 2 号 p. 82-88
Annual bluegrass (Poa annua L.) is one of the most serious weeds in golf courses in Japan. Recently, anecdotal reports of unusual types of this species have been made. In order to determine the extent and importance of these plants, a survey was carried out in 2000 by sending a questionnaire to superintendents of golf courses across Japan. Two hundred and twelve responses were obtained. The most common characteristics observed in the unusual P. annua plants were year-round growth, followed by prostrate habit and difficulty in control. This indicated that they were mostly identified P. annua L. var. reptans Hausskn. The number of golf courses infested by this variety has apparently increased since 1993. It occurs in up to 60% of golf corses in southern Kanto district, while less in the area south of the Tokai district. The most probable route of invasion by this variety is assumed to be as a contaminant of imported commercial turfgrass seeds. From the early 1990's, inter-seeding of new bentgrass cultivars on bentgrass putting greens and/or over-seeding of cool season grasses in winter on Zoysia turf of fairways, tee-grounds and green-edges were increasingly applied, particularly in southern Kanto. Infestation of the weed seems to have coincided with these turf improvement procedures. Plants appeared predominantly in putting greens suggesting their high adaptability to intensive mowing and rolling. The risks of weed contamination in imported turfgrass seeds are discussed.
