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Rings Around the Lawn
This article was published originally on 9/15/1995If your lawn is brown, you have lots of company. The summer of 1995 has been tough on turfgrass. Cool, wet spring weather slowed the growth of grass roots. Searing heat during parts of late June and July set the stage for a relentlessly hot, dry August and stressed-out turf.
Many browned-out lawns are just doing what comes naturally. Kentucky bluegrass, our dominant lawn grass species, is happiest in cool to mild temperatures with abundant moisture, so it grows and looks best in spring and fall. In the summer of '95, Kentucky bluegrass lawns that don't receive regular watering have gone dormant. They're not sick, just biding their time until cooler, moister weather allows them to green up and start growing again.
But some brown lawns have more complicated problems. A disease called summer patch has been unusually common and severe in Iowa and nearby states this summer.
Does your lawn suffer from summer patch? Describe your lawn problem in the following summer patch mini-quiz:
Summer patch is caused by a fungus that lives in the soil and attacks the roots. It nibbles on the roots during spring and fall, too, but shows its ugly self only in summer, when the lawn is stressed by heat and demands lots of water.
Summer patch damage ranges from slight to spectacular. A few rings may fade out in September, only to reappear during hot weather next summer. But under favorable conditions, hundreds of straw-colored rings can mass together, leaving only scattered tufts of green grass. This sort of wipeout usually requires overseeding or resodding to restore the lawn.
Summer patch thrives on stressed turf. So how do you avoid stressing your lawn in the summer? Here are some suggestions:
A cost-effective defense against summer patch is to take advantage of genetic resistance. Overseed damaged areas with turf- type tall fescues, perennial ryegrass, and/or resistant varietiesof Kentucky bluegrass. Mixtures of resistant varieties or blends of different species tend to give the best results.
Systemic fungicides have been used to suppress summer patch. The catch is that applications must be made at monthly intervals in early May and early June, before summer patch symptoms appear. Fungicides are an expensive option for home lawns, and their effectiveness can be erratic, especially when the nonchemical management tips listed above are ignored. Lawns that are shielded from severe summer stress and armed with resistant genes will dodge the summer patch bullet.
Year of Publication:
IC-470(23) -- September 15, 1995