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
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
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