Lawn problems
Patches of dead or dying grass are a sure sign of lawn trouble, but isolating the cause of the trouble is not always a simple matter. Lawns are attacked by a variety of pests, some of which do their work invisibly below ground, and by an array of fungus diseases whose effects on the lawn tend to look very much alike. To complicate the diagnosis, a number of lawn injuries caused neither by pests nor by disease resemble the damage done by such enemies. The chart on this page covers these miscellaneous ills, many of which are cured by such simple remedies as extra watering or a change in mowing height. On the following pages are charts explaining how to recognize and eradicate or prevent pests, lawn diseases and weeds. The best defense against such agents of destruction is vigorous health: a well-fertilized, well-watered lawn with a thick turf kept free of decaying vegetation and debris will be safer from attack, and better able to fight it off if it comes, than a neglected lawn. When pests, diseases, and weeds gain a foothold—or, in the case of fungus diseases, even threaten—chemical tfeatment generally is required.
Because chemical controls work in various ways, the manner and timing of their application may be critical. Fungicides, for instance, are more effective as preventives than as cures. They coat the stems and leaves of plants with a protective film that makes the plant a less attractive host to disease-bearing spores, thus discouraging the spores from germinating. A fungicide should therefore be applied in advance of an expected infection, and the application should be repeated at regular intervals as long as the danger exists. Under normal conditions the interval is 10 to 14 days, but if the weather is humid, a condition favoring fungus attack, and if the lawn is vulnerable because showers have washed away earlier applications, the interval can be shortened to as little as once every four to seven days.
Insecticides are seldom applied until after the pest strikes, but frequent observation will help you catch an infestation in its early stages. Most lawn insecticides are formulated to kill either by contact (with a penetrating poison for sucking insects) or by ingestion (with a stomach poison for chewing insects). Insecticide application techniques also vary with the eating habits of the pest. To kill those that operate aboveground, by chewing or sucking on stems and leaves, you should avoid washing insecticide off the plants. Supply the lawn’s moisture needs by a thorough soaking before applying the insecticide and then do not water at all for several days. To kill pests that operate underground by feeding on the roots, apply the insecticide to the lawn and then water thoroughly to wash the poison down into the root zone.
Pesticides come in various forms—as granules for use in spreaders, as liquid concentrates and wettable powders that are used in spraying equipment, and as ready-to-use dusts and liquids in convenient squeeze-plastic or aerosol containers. Many of them are mixtures, designed to take care of several lawn problems at once; check the label to make sure it contains the particular chemical you want. Read the label too for directions about amounts and application procedures, and follow them scrupulously. If the instructions say one tablespoon per gallon, do not conclude that two tablespoons per gallon will do the job more quickly or thoroughly; often the extra-strength mixture will simply damage the lawn. Also, heed the manufacturer’s precautions. Many of these chemicals are toxic or will burn the skin, and in addition may be harmful to birds, household pets and beneficial insects like honeybees if not used correctly. Never spray or dust on a windy day, never use insecticides, herbicides or fungicides while you are smoking, and never spray or dust around foodstuffs. Do not dump out leftover chemicals in puddles or piles where children, birds or household pets might get into them. Wash out sprayers and spreaders after use, and thoroughly wash your face and hands. Never use a sprayer of weed-killing chemicals for any other purpose. Store all chemicals in a safe place that is well out of the reach of children.
