Figure 2. Bipolaris leaf spot occurring on an older stand of vegetative bentgrass following warm and humid conditions during the summer. ryegrass, and fine fescues. Bipolaris served in the summer. It’s actually pretty rare for us leaf spot on cool-season turf mostly occurs on creeping bentgrass, esto see leaf spot on bentgrass durpecially older varieties of bentgrass ing the spring, but every season we (the old Washington and German get numerous reports of leaf spot vegetative bents are particularly on bentgrass in April and May besusceptible). In addition, Drechslera cause of circular pink or red-colored typically likes cool and wet condipatches of turf. In nearly every tions (59-64°F), while Bipolaris typi- one of these cases when a sample cally prefers hot and wet conditions is submitted we can’t find any (85°F and higher). As you might ex- evidence of leaf spot (which is not pect, Drechslera is more commonly typically a hard disease to diagnose observed in the spring and fall while microscopically because of their Bipolaris is more commonly obcharacteristic spores [Figure 3]) on
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