FLORIDA INSECTS:
Pesticides vs. Biological Control
Myakka River State Park
Florida
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Pesticides vs. Biological Control
Summary
"Pest management is the reduction of pest problems by actions selected after the life systems of the pests are understood and the ecological as well as economic consequences of these actions have been predicted, as accurately as possible, to be in the best interest of mankind".
Rabb, R. L. and F. E. Guthrie, 1970.
The use of pesticides in the control of insects has not been effective as we have seen by the return of the Mediterranean and Oriental fruitflies that have reappeared after massive spraying of the pesticide Malathion. And the use of pesticides has caused the extinction of many beneficial insects, as well as poisoning the water and the birds and reptiles who may have fed on the poisoned insects. Pesticides do not differentiate; they will kill the good as well as the bad. Extinction is final, there is no resurrection for any of the insects that are gone. As we saw by the story of the fireant, the native ants that were natural predators of the fireant were destroyed by the DDT spraying while the pest adapted and survived. Beneficial insects are often more susceptible to chemicals than the pests are. And the pests seem to build up an immunity to the pesticides which results in heavier applications of the poisons, causing even more harm to the environment.
A new form of insect control that has proved effective without eliminating the insect species and without harm to the environment is biocontrol.
Biological controls include:
- predators - either insects or insectivorous animals that eat insects.
- parasites - insects that lay eggs in or on the host insect. The larvae feed on the host, thus eventurally killing it. These parasitic insects are very specific as to the type of insect they use as a host and are not harmful to humans.
- insect pathogens - viruses, bacteria, fungi, nemotodes and other microorganisms that cause disease among insect pests.
There are three broad approaches to biological control:
- importation of natural enemies.
- conservation of natural enemies through farming and gardening practices that ensure their survival.
- augmentation of natural enemies through periodic releases which increase the overall numbers.
Because biocontrol does not work like a pesticide, some insects will be left on the crops. Biological control is meant to keep pests at a low level where they do little damage, but not eliminate them. For even those insects we consider pests have their place in the ecosystem and we destroy them at our own peril. Sinthya Penn of Beneficial Insectary stated in his paper at the Cornell Community Conference on Biological Control in April, 1996 that killing a target pest that results in even higher pest populations and/or "creating" secondary pests that are not controllable has created the desire to look at alternatives.
If you wish to learn more about biological control of insects in argiculture and gardening, I have provided the following resources:
WWW
Virtual Library on Sustainable Agriculture - Florida Plants Online
Florida Biotech Information Consortium
Cornell
University Biological Central: A Guide to Natural Enemies in N. America
Midwest
Institute for Biological Control
Nematology
- University of Nebraska-Lincoln: Nematods as Biological Control Agents
of Insects
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