Dollar spot has arrived on golf courses. The standard mid- to late May fertilization of 0.75-1.0 lb N/1000 sq. ft. with primarily slow release N should have helped minimize some dollar spot. On golf courses with a long history of dollar spot, first and foremost review the fertilization practices and increase the annual N if possible. Other cultural practices to reduce dollar spot include early morning rolling, syringing and/or mowing to minimize free water on the leaf surfaces. It makes sense to use fungicides early in the season at or before the first outbreak, rather than waiting for symptoms to become obvious. Although this seems to conflict with typical IPM strategy to apply only after symptoms approach an intolerable threshold, we feel early applications will suppress inoculum levels, thus limiting disease pressure and reducing fungicide use over the whole season. If you choose to apply early (or whenever you apply fungicides for that matter), be sure to rotate fungicides and to tankmix systemics (acropetal penetrants) with contact fungicides to help minimize the resistance risk.
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