Best management practices for anthracnose on annual bluegrass turf

e rc h re se ar ch ea rc h re se ar ch re se ar ch re se ar ch r rc h re se ar ch Best management practices for anthracnose on annual bluegrass turf 22 Green is Beautiful • Winter 2010 Anthracnose (caused by Colletotrichum cere-ale) is a destructive fungal disease of weakened turf that occurs throughout the U.S., Canada and Western Europe (15) and is particularly severe on annual bluegrass (Poa annua). The frequency and severity of anthracnose epiphytotics on golf course greens has increased over the past decade (13,14) and is thought to be associated with some of the management practices used by superintendents to improve playability and ball-roll distance. Combinations of management factors may be enhancing the severity of this disease. Scientists within the NE-1025 multistate turf research project are studying the biology, ecology and management of anthracnose of annual blue-grass turf on golf courses. They are examining the biology of the pathogen, assessing fungicidal control and fungicide resistance development, evaluating the effect of cultural practices on anthrac-nose severity and developing annual bluegrass and bentgrass selections for resistance to this disease. Completed and ongoing field trials within this five-year project (2005-2010) have evaluated registered and experimental fungicides, fungicide programs and annual bluegrass management practices, including nitrogen fertility, chemical growth regulation, mowing, rolling, topdressing, verticutting and irrigation as well as the potential interaction among practices. Ultimately, results from these experiments will be used to devise a comprehensive set of best management practices for the control of anthracnose disease on golf courses. Anthracnose can be found on cool-and warm-season turf in roughs, fairways and tees, but often the disease is most destructive on annual bluegrass maintained at a putting green height of cut. Outbreaks are also increasingly common on creeping bentgrass (Agrostis stolonifera) and may develop on other cool-season turf species including ryegrasses (Lolium species), fescues (Festuca species), Ken-tucky bluegrass (Poa pratensis) and velvet bent-grass (A. canina). Although the disease is often most severe during warm weather, outbreaks may occur throughout the year, causing either a foliar blight or a basal rot of leaf sheaths, crowns and stolons (15). Anthracnose is often present on turf mowed at a higher height without producing severe damage , which suggests that plant health (vigor and stress) is a major factor that determines disease severity. The disease can cause extensive injury on turf maintained at low fertility, very low …