Environmental Engineering Reference
In-Depth Information
selected pesticides mentioned or discussed here may be restricted or
unavailable for various reasons. In such cases, the local pest-control
bureau may suggest suitable alternatives.
Pesticides
Pesticides are chemicals used to control pests. They are usually organic
compounds that interfere in some way with one or more physiological
processes in the pest organism. To be effective, they must affect the pest
at some minimum concentration for a sufficient period of time. Effective
pesticides are those that reduce pests' populations or their activity to a
tolerable level, not necessarily that eliminate the pest completely. A few
spots on the leaves or the presence of a few insects in the turf usually does
not cause damage or reduce turf's quality below an acceptable level.
Complete control - i.e. killing every single pest individual - even when
it is possible, is usually unnecessary and would require higher doses of
pesticides, which are both costly and harmful to the natural environment.
Fate of pesticides
Pesticides are subject to many forces operating within the natural envir-
onment (Fig. 11.1). During application, a portion of the pesticide spray
Pesticide
Photodecomposition
Volatilization
Wind drift
Run-off
Adsorption by
thatch and soil
Absorption
by plants
Chemical reaction
Microbial
decomposition
Leaching
Fig. 11.1. Once released to the environment, pesticides undergo numerous
transformations.
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