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What are the best cures for fungus type lawn diseases. We've tried infrequent deeper watering, which makes it worse, higher mowing in the hotter months, airation shoes, and everthing else suggested. We know we have clay under the topsoil.

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The best "cure" for fungus in turfgrass is prevention. By eliminating fungus's preferred habitat, you will eliminate the disease. All of the suggested cultural practices you mention (infrequent and deeper watering, aeration, and raising the mower deck in summer) are good practices. But there is one critical element you did not mention - thatch.

Thatch is the spongy layer of dead and dying leaf and root tissue layered on top of the soil but beneath the grass blades. If this layer is thicker than one-half inch, it may be allowing fungus to stay protected.

Diagnose your thatch problem by digging out a cross-section slice of lawn. Measure the distance between true soil and growing grass blades. If it is as thick as three-quarter inch, you have a problem.

To decrease thatch, core aerate twice annually. Be sure that the lawn is aerated very well - run the aerator over the same area twice (in two different directions, just as you would fertilize with a drop-spreader). You needn't remove the cores. Aerate in spring and again in late summer or fall.

Are you cycling your irrigation? If you have clay soil under topsoil, irrigate as if the entire soil profile was clay. This assures good water percolation through the root zone.

For more information about Basic Turfgrass Care, see the USU Extension publication with that title at http://extension.usu.edu/files/publications/publication/HG_517.pdf

 

Posted on 23 Apr 2007

Maggie Wolf
Horticulture Agent, Salt Lake County

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