Pest Control and Pesticide Usage

We are now well into the gardening season. Our fruit trees have bloomed and have fruit, our vegetable plants are getting larger, and some early established crops, such as broccoli and green,s are being harvested. Novice gardeners may wonder what to expect next, but the "pro green thumb" knows what will most likely occur soon—the invasion of insects and disease. For Texans, this invasion is "as sure as death and taxes," as the old saying goes. When the invasion occurs, you must decide whether you will fight or forfeit. If you fight, you will have to use "those poisonous pesticides" which we hear so much about; if you forfeit, you will let the insects and disease destroy 2/3 of your crop, and (hopefully) harvest only 1/3. I prefer a middle-of-the-road approach—use pesticides when needed, but not in excess. Pesticides are only as safe as the person using them.

Pesticides and medicines have much in common. Properly used, they can cure specific problems, but other problems can arise if directions are ignored or fall into unsuspecting hands. You simply can't afford to be careless.

The medicine chest has long been known as a source of potential problems. Reports from the Poison Control Center indicate that children under the age of 5 are involved in more than 1/2 of all the accidental swallowings involving a wide range of substances. Common aspirin is the leader in ingestions and fatalities.

Youngsters are inquisitive. They look for interesting new places to play. Unfortunately, too many of these places are areas used to store many common household products, including pesticides. Less than 5% of all reported accidental poisonings were from exposure to pesticides. Many of these resulted from storage in the cabinet under the kitchen sink.

Gardeners should know the "ABC's" of safe pesticide usage. They include:

A. Keep all pesticides in their original labeled container, and always avoid transferring to them to containers ordinarily used for soft drinks or fruit juices.

B. Enforce a no-play rule for children when using pesticides. A
couple of no-no's will certainly be better than the "Oh no!" when an accident occurs.

C. Never trust your memory. Before using any pesticide—
STOP and read the label! If you can't, or won't, follow directions, you really should not be using any pesticide. Each is scientifically designed to give best results at the exact rate specified on the label.

D. There are many different types of pests so it may take different varieties of pesticides with specific formulations for proper control.

E. Don't apply the aspirin theory—that if one is good, then twice as much will be better. It simply isn't true with pesticides and could cause poor plant growth.

F. When you are handling concentrated materials, it's a good idea to follow the lead of professionals and wear protective clothing.

G. Final clean-up is important. Wash and bathe thoroughly after use, and give special attention to cleaning and checking your equipment to make sure it's in good condition the next time you need it.

Above all, read the label and use the product as directed. The pesticide label is a legal document. Professionals with the Texas Cooperative Extension, or even nurserymen, do not have the legal right or justification to make recommendations for a product other than what appears on the product's label. If you misuse a chemical, meaning that you use it other than as precisely recommended on the pesticide label, no one has the authority to condone your action or recommend consumption of the sprayed crop.

Most insects are detected and controlled using a recommended insecticide. Worms or caterpillars are the most conspicuous to gardeners. Worms (caterpillars) come in a variety of colors and shapes, but all do damage to plants by eating holes in leaves. They feed on most garden vegetables. Entire plants can be eaten by caterpillars if they occur in large numbers. Caterpillars can be easily controlled by using Dipel, Thuricide, Bio-Spray or Biological Worm Killer. These materials contain the bacteria Bacillus thuringiensis that kills only caterpillars and does not harm beneficial insects. Good coverage and the wetting of upper and lower leaf surfaces are necessary for best control. To insure that wetting occurs, mix one teaspoon of a liquid detergent per gallon of spray.

Control other insects by using insecticides such as diazinon, malathion, or endosulfan (Thiodan) which can be used legally on the appropriate crop. Avoid the blanket use of any specific insecticide. Otherwise, insects may become resistant to the insecticide. It is a good idea to switch insecticides periodically.

Insects can be harmful, but disease can be disastrous. Diseases must be prevented, not cured. There are 2 main diseases which cause this disaster every spring. Early blight (Alternaria) and septoria leaf spot are the culprits. Early blight is characterized by irregular brown spots that first appear on older foliage. With age, the spots show concentric rings forming a target pattern. A yellow diffuse zone is formed around each spot. Although this fungus disease can be observed throughout the year, it is most common during the fruiting period. The more fruit that a plant has, the more susceptible to and disastrous are the effects of an early blight infection. The fungus is favored by high humidity and high temperatures. The only control is prevention that begins when the plant is transplanted. During periods of high humidity, which includes most of the spring, apply a fungicide weekly. The best fungicide to use is one containing maneb, or chlorothalonil (Daconil, Vegetable Disease Control—often sold as Multipurpose Fungicide—or Fertilome Broad Spectrum Fungicide).

In closing, consider this point. Many of you have used sulfur, ashes, epsom salt and even flour for organic control of pests. I would warn you that such use without a legal, labeled approval is in violation of the law. I would hate to see San Quentin full of organic gardeners! For organic solutions, see:
http://aggie-horticulture.tamu.edu/plantanswers/publications/miniput.html