Golf Course Management

FEB 2017

Golf Course Management magazine is dedicated to advancing the golf course superintendent profession and helping GCSAA members achieve career success.

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Page 88 of 127

02.17 GOLF COURSE MANAGEMENT 77 Once established, Amynt as are impossible to remove from forest environments. These soil sharks can hitchhike in shipments of mulch and in containerized plants from garden cen - ters, and reports of their damage to gardens, mulched beds of ornamental plants and even lawns are increasing (1). While A. peiensis does not seem to be as damaging as its cous - ins in forest and garden settings, it can nev- ertheless wreak havoc once established on golf courses. Casting activity and seasonal development Amynt as peiensis produces large, sandy, often sinuous casts on sand-based greens (Fig - ure 2A,B). The casts differ in appearance from the smaller piles of smooth, muddy aggre - gates (Figure 2C) deposited by the common, topsoil-dwelling Aporrectodea, which are the predominant earthworms on temperate- and transition-zone golf fairways and sports fields. They also differ from the volcano- or dome- shaped mounds of fine particulate sandy soil deposited around nest entrances of the turf - grass ant, Lasius neoniger (Figure 2D) (5). The casts quickly dull the blades of reel mowers and accumulate between the roller and bed knife, upsetting the tolerance needed for a clean cut and requiring frequent stop - ping and cleaning. The casts also muddy and smother the grass when smeared or com - pacted by tires or foot traffic (Figure 3). Casts are expelled at the entrance to their burrows both day and night during all seasons, but es - pecially during the warm months from mid- spring until autumn. We found that infested greens mowed in the morning were already covered with fresh casts by afternoon. Casting is especially heavy for several days after rain. On putting greens, little or no casting occurs in winter (Figure 4). The earthworms themselves are dark olive- green, greenish-brown or greenish-gray, typi - cally darker on top and lighter underneath, and they thrash and coil up when disturbed (Figure 5). They produce a foul-smelling se - cretion, the odor of which remains on the fin- gers if the worms are handled. Except for the clitellum (the thickened band toward the front end on adult earthworms), each body segment is encircled by a complete ring of tiny bristles. Juveniles lack a clitellum but have the same greenish coloration as the adults (Figure 5). Little is known about seasonal develop - ment of A. peiensis or where they over- winter. To clarify those points, we used a golf cup-cutter to collect monthly samples of worms from the same heavily infested sand- based putting green for a year. There was much overlap of life stages, but adults tended to predominate in May and June and again in autumn, whereas juveniles were more abundant in summer. We observed no cast - ing and found no active life stages in sand- based greens in winter (December to Feb - Figure 2. A, B: Typical Amynthas hupeiensis casts on a sand-based green. Note the sinuate form. C: Smooth casts of a typical topsoil-dwelling earthworm. D: The casts of A. hupeiensis also differ from the volcano- or dome-shaped mounds of fine particulate sandy soil deposited by the turfgrass ant (Lasius neoniger). A B C D

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