The Ohio State University

Home TurfNotes As the wettest June on record came to an end in Central Ohio, disease activity has begun to change. For most of this spring red thread has dominated Kentucky bluegrass (Poa pratensis) turf stands. However, in the past week, dollar spot has taken its place - in some cases literally. On some of the athletic fields here on campus, where red thread symptoms had persisted, dollar spot is now present. The increasing temperatures along with the wetness and increased dew periods has enhance disease development. At the moment the areas where dollar spot is most likely to occur on Kentucky bluegrass is where it is under irrigation.

Dollar spot symptoms can be confused from a distance with those of the bluegrass billbug. To differentiate the two, "tug on" the plants within the infected area. If they are easily removed and look like they have been chewed off at the base it is most likely bluegrass billbug. If the injured plants are not easily removed, check the leaf blade for the classic leaf lesion (hour-glassed shaped, bleached with a brown border extending the width of the leaf).

To minimize dollar spot injury maintain adequate fertility levels, minimize periods of wetness, and in some cases, if the disease becomes severe, fungicide treatments maybe necessary.

As a compliment to this posting, a dollar spot turf podcast is available.
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Posted by Karl Danneberger