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Cornell University : Cornell Cooperative Extension
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| Yates Association |
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What Are Pesticides? |
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August 21, 2001 The Environmental Protection Agency (EPA) defines a pesticide as "any substance or mixture of substances intended to prevent, destroy or mitigate any insects, rodents, fungi, or weeds or any other forms of life declared to be pests." This definition includes biorational and chemical pesticides. Biorational pesticides include bio-chemicals and microbial products. The microbials consist of two groups: products whose active ingredients occur in nature and products whose active ingredients are genetically engineered. Chemical pesticides are chemicals of either natural or synthetic origin that kill or protect against pests such as insects, weeds, plant pathogens, rodents and other kinds of animal and plant life. Pesticides
are broken down into as many as two dozen or more categories such
as Insecticides, Fungicides, Herbicides and Repellents.
Types of Pesticides: Insecticide soaps are especially formulated soaps containing potassium or sodium salts of certain fatty acids. They are popular because of their low toxicity to humans, pets and many beneficial insects. They work only on contact and once dried will not affect the insect. It is important as with most all insecticides to treat the undersides of leaves as well as wherever the insects are seen. Some plants may be sensitive to insecticide soaps. Horticultural
oils are a refined petroleum oil manufactured specifically to control
plant pests. They are paraffinic, degrade rapidly through evaporation
and also have low toxicity to humans and wildlife when used properly.
Horticultural oils may be applied both in summer and when plants are
dormant. Again care should be taken to follow the label directions.
They are relatively non-toxic to the applicator and leave no toxic
residue. Horticultural oils interfere with the respiration and membrane
function causing suffocation and disrupt feeding activities of certain
insects. They are most effective against eggs and other immature forms
of insects. Botanicals are derived from plants. Some are as toxic as synthetic chemicals or even more so. Botanicals are accepted by organic gardeners. Mineral Pesticides are what the name indicates coming from the earth such as copper and sulfur. Care must be taken with their use as to their safety. Diatomaceous earth is a dust made from fossilized shells of tiny aquatic organisms. These are only effective until the first rain after application. Synthetic Chemical Pesticides have a wide range of effectiveness and toxicity. Years ago there were chlorinated hydro-carbons such as DDT and Chlordane which are highly toxic with a long residual effect building in the food chain. They have been banned for use in this country. Many familiar products such as Dursban and Diazinon have been removed from the shelves of department stores and garden centers. These can only be used by "Certified Pest Control Applicators". Another down side of these chemical compounds is that they are harmful to predatory insects. Some chemical herbicides are selective in that they kill certain types of weeds in lawn and not injure grass. An example is 2-4-D. Other herbicides such as Round-Up work only through the chlorophyll part of plants (green leaves). Round-Up looses its effectiveness and most of the toxicity when it hits the ground or brown bark. It is relatively safe to use in its diluted application form. Chemical Pesticides, like medicinal drugs, are constantly being developed to target specific pests and different stages in its life cycle. Pesticides for home and garden use contain active ingredients combined with other ingredients to make them easily usable and safer. They are available as dusts, sprays, pressurized cans (aerosols), granules, and baits. There are multi-purpose mixtures which combine more than one pesticide, sometimes fertilizers, targeted for multiple pests which attack tomatoes, lawns, or roses. There are a wide variety of ways pesticides may be applied. Dusters, sprayers, granule spreaders are available for home and garden use and of course the commercial or professional operators have their specialized equipment. There are several very important approaches to the use of pesticides. The first is to identify the pest or problem. Next what kind of plant or area is affected? How severe is the problem, can you live with it? How does the weather or the time of year figure in? Maybe the problem is short lived and will correct itself. A relatively new approach to pests and pesticides is being taught to farmers and home gardeners alike. It is called Integrated Pest Management (IPM). It is a way of growing healthier plants by using varieties that are more resistant to pests. Certain pre-planting preparations will cut down on pest problems later. Improving or changing cultural practices is another concept of IPM. The Cornell Cooperative Extension is providing education along these lines. If all
else fails and a pesticide is needed, find out what will work best
in your situation. Always read the entire contents of pesticide labels.
Federal law requires a multitude of things to be included on the label.
A pesticide must meet standards set by the EPA and NY State Department
of Environmental Conservation (DEC). A product approved for use in
another state may not be approved for use in New York state. The label
will identify the pest controlled and should be carefully studied
before purchase to be sure it is the best one for our purpose. The
correct level of dilution, mixing or rate of application required
will also be on the label. It will also identify cautions and warnings
needed in handling, mixing, using, and storage as well as proper disposal
and the level of toxicity.
Wear all safety equipment and any special clothing called for on the label. Concentrated pesticides can be extremely dangerous so use great care in mixing them. All garden chemicals must be stored out of reach of children, pets and unsuspecting adults as well. Every container containing a mixed pesticide must be labeled with the name of the pesticide and its concentration clearly visible. Unlabelled pesticides are "accidents" that have found a place to happen and our memories are not always perfect. As airline pilots always read the check lists every time they fly, not trusting to memory, we should heed their practice and not rely upon our memories when mixing and using pesticides. Always reread the label before mixing and use. Many accidents occur to plants because the mixed concentration was incorrect. Another good idea is to avoid multiple use of applicators (sprayers). Some pesticides are not easily cleaned and enough residual chemical remains to do harm. A couple of final comments: plastic one gallon milk containers are made to break down rapidly in land fills and are not safe to store mixed pesticides, and glass containers can break with disastrous results. If you
need advice or have questions for the Master Gardeners, call the Cooperative
Extension at 315-536-5123 leaving your name, question for us to research,
phone number and a time we can call you back. We love to hear from
you and answer your questions. Cornell
Cooperative Extension Yates Association |
