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Ch. 6, pp. 22 - 26

Direct Kill

Fine mists of herbicides can drift to nearby crops or landscape plants and kill them. Bees and other pollinators can be killed if a crop is treated with a pesticide when they are in the field. The natural enemies of pest insects can also be killed by pesticides. Life in streams or ponds can be wiped out by accidental spraying of ditches and waterways, runoff from sprayed fields, and careless container disposal. If more than one pesticide will control the pest, choose the one that is the least hazardous to the environment and most useful for the situation. To protect beneficial insects, avoid excessive use of insecticides - spray only when crop and pest populations require.
Protecting Insect Pollinators

Gardeners should give special consideration to protecting insect pollinators, such as the honey bee, from insecticide poisoning. Insecticides highly toxic to bees have restricted application times when being applied to crops frequented by honey bees. Bees are not active in late evening and early morning. Do not apply insecticides when temperatures are unusually low because residues will remain toxic much longer.
Persistence and Accumulation

Although most pesticides break down quickly, remaining in the environment only a short time before being changed into harmless products, some pesticides break down slowly and stay in the environment for a long time. These are called persistent pesticides. Some persistent pesticides can build up in the bodies of animals, including man. These pesticides are called accumulative. Most persistent pesticides have very limited usage or have been removed from the market. For example, chlordane is a persistent pesticide and its use was limited to termite and fire ant control but has been removed from the market.
Pesticides Move in the Environment

Pesticides become problems when they move off target. This may mean drifting off the target if in the form of dust or mist, moving with soil particles by erosion, leaching through the soil, being carried out as residues on crops or livestock, or evaporating and moving with air currents.
Safe Use Precautions

Following safety precautions and using common sense can prevent harm from pesticides. Here are the minimum safety steps you should take.
Before buying a pesticide, identify the pest to be controlled. Then find out which pesticide will control it. If there is a choice of several, choose the least hazardous product.
Before purchase, read the label of the pesticide you intend to buy to ensure that the host plant (and pest) are listed on the pesticide label and that the pesticide is not phytotoxic to the plant being protected. Also check safety conditions for use, such as special equipment, protective clothing, restrictions on use, and environmental precautions needed.
Before applying the pesticide read the label again. Be sure of proper application and safety measures, including protective clothing and equipment needed, the specific warning and precautions, with what it can be mixed, mixing instructions, application to harvest period for fruit and vegetables, crops to which it can or cannot be applied, and other special instructions.

Compatibility occurs when two or more pesticides can be mixed together without reducing their effectiveness or harming the target. For instance, carbaryl (Sevin) is often combined with a miticide such as Kelthane in order to kill both insects and mites at one time. Synergism is the action of two materials of the same type which used together produce a greater effect than the sum of the materials when used alone. One of the materials when used alone may not affect the pest, but greatly increases the total effect of the two when used together. Example: Chemical A kills 60%, Chemical B kills 20%, Chemical A and B together kill 98% of the pests. Synergism may increase control or require less chemical. It may also be more harmful to a nontarget organism. A synergistic effect can also be undesirable, causing death or damage to the organism that is being protected. It should be stressed that no chemicals should be mixed together unless the label specifically says they are compatible.


Some pesticides are packaged specifically for home garden use. These products are packaged in small quantities, i.e., pints, quarts, ounces, or pounds. They are seldom highly toxic pesticides and are usually in low concentrations. The label rate is given in spoonfuls per gallon or pounds per 1000 square feet.
Because of the small label size, home garden products may not list all of the plants and/or pests for which the product may be registered for use. For example, one manufacturer sells Diazinon 25% EC as Fruit and Vegetable Insect Control and Diazinon Insect Spray. Both are basically the same product, but plants and pests listed vary greatly. This situation causes some confusion in pesticide application and stimulates the purchase of excessive amounts of pesticides.
Products packaged for the commercial grower may appear to be less expensive, but consumers should not be tempted to use them. They are generally more toxic than those for home use and require special protective clothing and equipment for application. These products are more concentrated and in larger containers than the consumer could expect to use or safely store, and are much more difficult to calibrate and mix correctly, since rates are usually based on a per-acre system.
A few products extremely toxic to humans or the environment are classified by the EPA as restricted use pesticides. The label will state "restricted use pesticides for retail sale to and application only by certified applicators, or person under their direct supervision." A license from the State Department of Agriculture is required by law for purchase and use of restricted use pesticides. This licensing is intended for commercial growers and does NOT automatically clear the use of these products by the home gardener. If you must use pesticides from the commercial trade, use extra caution to protect yourself, your family, and the environment.
Pesticides and Organic Gardening

Although it is questionable whether we could raise all crops without the use of pesticides, it is certainly true that we can reduce the amount of pesticides we use by careful and efficient use. There are some steps to consider before automatically turning to a pesticide. First, determine if control measures are really needed. Is the problem severe enough to warrant treatment? If the cost of treatment is less than the predicted loss, the economic threshold has been reached, and treatment is necessary. Consider alternative control measures. Some examples are cultivating instead of using an herbicide, and removing and destroying diseased plant parts rather than using a pesticide.
The next step is integrated control. This is probably the best answer to pest control. In this situation, the wise use of pesticides is combined with alternative methods, such as conservation practices, to encourage natural enemies of the pest. For example, a simple integrated control program could be used on a golf course for grub-proofing against Japanese beetle larvae. A chemical pesticide would be used to protect the more valuable sodded areas of the fairways. Milky spore disease, which is a commercially produced biological control for Japanese beetle larvae, would be applied in the roughs. The chemical pesticide would give immediate protection to the sodded areas while the milky spore disease becomes established in the rough. Then, as the chemical breaks down in the more valuable areas, milky spore disease would move in. Once milky spore disease is established, no more chemical treatment is usually needed to protect the turf.


The registration and use of pesticides are governed by the E.P.A. and the Arizona Department of Agriculture and Consumer Services. Under the amended Federal Insecticide, Fungicide, and Rodenticide Act (Federal Environmental Control Act of 1972) it is illegal to use a pesticide on a crop unless the crop is listed on the label. You may not exceed the given rate of application on the label. Fines and other penalties change and vary according to laws broken.
Under the law you are liable for misuse of pesticides on your property. Recent court rulings extend your liability to include misuse by commercial applicators you hire. Serious misuse by gardeners usually results from drift, leaching of a pesticide onto non-target plants, or the direct treatment of the plant by a wrong pesticide.

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