Dying Grasses

• A number of circular patches are forming in my yard. The centers remain green, but the edges are dying. What should I do?

• During hot, humid weather, patches of slimy, water-soaked grass appear. When the spots dry, the leaves turn brown and die - all within 24 hours. What's wrong?

• Why are brown blotches appearing on my leaf blades and small, circular areas of my lawn dying?

• My yard has large, circular patches of brown grass. The leaves first appear water-soaked, but dry and turn dark brown. What should I do?

• There's a white crust on portions of my soil and the grass in those areas is slowly dying. How can I correct the problem?
  

A number of circular patches are forming in my yard. The centers remain green, but the edges are dying. What should I do?

This tell-tale "frog-eye" pattern is caused by several fungi. Called Fusarium blight, this is generally only a problem from June through August. Two of the most susceptible grass varieties are bentgrass and Kentucky bluegrass. Lawns are particularly susceptible to the disease when they are under stress from drought. Once these fungi go to work in your yard, you may have trouble stopping them.

Solution: Your best bet may be to re-seed with resistant grass varieties. Even then, I'd suggest treating the whole lawn with a fungicide containing benomyl or iprodione next year. Complete control is difficult to achieve.

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During hot, humid weather, patches of slimy, water-soaked grass appear. When the spots dry, the leaves turn brown and die - all within 24 hours. What's wrong?

If your infected blades mat together when you walk on them and white cobweb-like threads can be seen in the early morning, my guess is you've got Pythium blight (cottony blight). Lawns under stress are most susceptible, particularly those with dense, lush grass. Be careful of this fungus, because it spreads easily. Flowing water, lawn-mower wheels and even your shoes can spread the disease. And because its works so quickly, your entire yard can die in literally hours. Solution (Your only hope): Treat your yard with a fungicide containing chloroneb or ethazole as soon as you notice the disease. Repeat the treatment every five to 10 days until the symptoms disappear. Severely infected areas often don't recover, so you may need to re-seed your lawn. To prevent this problem before it gets a foot-hold, avoid over-watering - especially in newly seeded areas - and make sure you've got good drainage.

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Why are brown blotches appearing on my leaf blades and small, circular areas of my lawn dying?

It sounds like you've got a case of dollar spot. This fungus is active during warm, wet weather (usually May to June and September to October). Lawns with moisture or nitrogen deficiencies are particularly susceptible. While dollar spot rarely causes permanent damage, it may take the yard several weeks to recover. Solution: I'd use a fungicide containing chlorothalonil, iprodione or thiophanate. You'll probably need two applications, spaced seven to 10 days apart. You can keep dollar spot at bay by increasing nitrogen applications, keeping thatch at a minimum and providing adequate water.

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My yard has large, circular patches of brown grass. The leaves first appear water-soaked, but dry and turn dark brown. What should I do?

If you live in a warm, humid area, you may have brown patch. This fungus attacks lush, tender growth, so you'll usually find it in yards with excessive nitrogen. Often only the blades are affected and the grass will recover. However, severe infections can kill your grass.

Solution: To stop brown patch, you'll need a fungicide with chlorothalonil and at least three treatments spaced seven-to-10 days apart. To prevent it, avoid heavy doses of nitrogen fertilizer, keep your thatch under control and aerate your yard regularly. 

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There's a white crust on portions of my soil and the grass in those areas is slowly dying. How can I correct the problem?

You're probably looking at salt damage caused either by insufficient watering or poor drainage. The problem: when water evaporates from the soil, the dissolved salts are accumulating near the soil surface.

Solution: The only way to eliminate excess salts is to wash them through the soil with water. If the damage is restricted to a few low spots in your yard, simply fill the areas. If the entire lawn drains poorly, try regular aerating. And, if drainage isn't the problem, increase the amount of water applied at each watering by 50 percent or more to leach the salts below the root zone of the grass.

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