From Penn State News by Jeffrey Mulhollem:
Dollar spot — the most common, troublesome and damaging turfgrass disease plaguing golf courses — is becoming increasingly resistant to fungicides applied to manage it, according to Penn State researchers.
An aggressive and destructive disease caused by the fungal pathogen Clarireedia jacksonii, dollar spot overwinters in plant tissues, often re-emerging in multiple epidemics throughout the year over the spring, summer and fall. The symptoms on highly maintained, closely mown turf typically consist of small patches of bleached plants that are unsightly and can affect playability of putting greens or fairways.
In the northern United States, more money is spent on fungicides aimed at controlling dollar spot than any other turfgrass disease, pointed out researcher John Kaminski, professor of turfgrass management and director of the Golf Course Turfgrass Management Program in the College of Agricultural Sciences. He noted that golf courses spend hundreds of thousands of dollars applying fungicides six to nine times a year to control the fungus.
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