How To Eliminate Brown Grass Spots

July 19, 1986|By Tom Mac Cubbin

QUESTION: The leaves of our newly plugged St. Augustine turf are full of brown spots. How can we stop this problem?

ANSWER: This turf problem is usually not as serious as it looks, but when it is out of control it will need a fungicide treatment. A fungus causes gray leaf spot disease.

It loves hot, humid weather and often spreads into well-established lawns. Excessive irrigation and, of course, summer rains spur the organism into growth.

The fungus produces small brown spots on the foliage early in the life cycle. Gradually, an ash-colored center develops.

Affected blades will eventually wither, giving a scorched appearance. The disease appears to select newly planted turf as a prime target, sometimes severely inhibiting growth.

No control is needed if there are only a few spots. But in severely affected areas, apply the fungicide chlorothalonil, which is often marketed as Doconil.

Q: What is the secret to keeping hydrangeas blue? Ours are now a poor pink. A: Acid soils with available aluminum will change pink hydrangeas to deep blues. When the planting becomes pinkish, the soils are neutral or alkaline.

Make the soil more acid and add aluminum with aluminum sulfate, available from local garden centers. Use the product at the rate of two tablespoons per plant dissolved in two quarts of water. Drench surface soil.

Gardeners can begin with two applications equally spaced throughout the summer and one during spring before flowering to give the blue color. Do not overapply the product as aluminum can reach toxic levels in the soil.

Q: We have an invasion of crawling insects. Many creep into the pool overnight. Where did they come from and how can we obtain control?

A: Your enclosed specimen should be able to creep better than most bugs on legs that often number more than a hundred. It's the millipede that some call thousand leggers.

They are regular landscape visitors living under stones, flower pots, boards or mulch layers. After heavy rains or cold they may migrate in search of better conditions. That is when they fall into your pool.

Millipedes feed on decaying plant matter. Some people complain of the insects consuming fruits and vegetables, but normally only after the produce becomes overly ripe.

They tend to coil up tightly when disturbed and some can secrete a foul- smelling fluid. Mostly they are just a nuisance that you should scoop out of the pool.

If outdoor control is needed a spray of Sevin, Baygon or diazinon where they hide should help reduce disturbing populations.

Q: The African lilies have produced big seed stalks. Can these be cut off or do I have to wait until they naturally decline?

A: Remove stalks of the African lily, also called lily-of-the-Nile and agapanthus, that have finished flowering and now are forming seeds.

The reproductive process is taking nourishment from the plants. The energies can better be put into new leaves or next year's blooms.

Cut the fleshy stalks back to the ground and discard. Perform this treatment with any flowering plant. With some, it will encourage more blooms during the remaining season.

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