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
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
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
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