A SYNOPSIS OF THE PESTICIDE PROBLEM
81
populations. The essence of all pesticide problems, therefore, is one of
population ecology. All other approaches are simplifications imposed
for the purpose of scientific analysis. This has the important corollary
that the results of analysis are likely to be misleading unless they are
related to the system as a whole: in other words resynthesis is essential.
Of course this concept applies to all ecological work, but there is abundant
evidence to show that it is frequently forgotten in pesticide research.
For example, it is often thought that effects in the field can be reliably
predicted from simple toxicity tests.
Misunderstanding about the nature of pesticide problems is probably
reinforced by the use of the term “side-effects”. For commercial and
pest control reasons emphasis has to be made on the pesticide and the
pest; as a result all other effects are thought of as “outside” the essential
pesticide/pest relationship. It is then very easy to fall into the error of
thinking that the actual reaction is
pesticide --f pest ( f side-effects)
_ _ _ _ _ ~ ~
~
I believe that many of the misunderstandings about the effects of
pesticides stem from this way of thinking. It might be countered by
the use of the term “biocide”, since this emphasizes the whole effect
of the chemical agent, not just the intentional effect. On the other
hand it could be argued that many factors other than pesticides are
biocidal.
Once it is recognized that all pesticide applications consist of a toxic
factor impinging on a highly complex system, useful deductions can be
made.
1. In studies on the effects of pesticides, a scientist is always dealing
with the effects of a factor (which can be accurately described) on a
system whose nature is scarcely understood at all. This is because
the complexity of ecosystems is such that in no case have their
workings been demonstrated. At best we have crude models illustrating what are believed to be salient features.
2. At any one time the population size of each species in an ecosystem is the result of a number of intrinsic and extrinsic factors.
Therefore, even if the exact physiological response of a species to a
pesticide can be predicted this will not necessarily demonstrate
whether the species will increase or decrease as a result of the
application of the chemical.
3. The pesticide will impinge at all levels of organization: at levels
of the cell and the organ, and a t the levels of ihe individual, the
population and the ecosystem. Therefore the most adequate explanation of pesticide effects consists of a synthesis of information
81
populations. The essence of all pesticide problems, therefore, is one of
population ecology. All other approaches are simplifications imposed
for the purpose of scientific analysis. This has the important corollary
that the results of analysis are likely to be misleading unless they are
related to the system as a whole: in other words resynthesis is essential.
Of course this concept applies to all ecological work, but there is abundant
evidence to show that it is frequently forgotten in pesticide research.
For example, it is often thought that effects in the field can be reliably
predicted from simple toxicity tests.
Misunderstanding about the nature of pesticide problems is probably
reinforced by the use of the term “side-effects”. For commercial and
pest control reasons emphasis has to be made on the pesticide and the
pest; as a result all other effects are thought of as “outside” the essential
pesticide/pest relationship. It is then very easy to fall into the error of
thinking that the actual reaction is
pesticide --f pest ( f side-effects)
_ _ _ _ _ ~ ~
~
I believe that many of the misunderstandings about the effects of
pesticides stem from this way of thinking. It might be countered by
the use of the term “biocide”, since this emphasizes the whole effect
of the chemical agent, not just the intentional effect. On the other
hand it could be argued that many factors other than pesticides are
biocidal.
Once it is recognized that all pesticide applications consist of a toxic
factor impinging on a highly complex system, useful deductions can be
made.
1. In studies on the effects of pesticides, a scientist is always dealing
with the effects of a factor (which can be accurately described) on a
system whose nature is scarcely understood at all. This is because
the complexity of ecosystems is such that in no case have their
workings been demonstrated. At best we have crude models illustrating what are believed to be salient features.
2. At any one time the population size of each species in an ecosystem is the result of a number of intrinsic and extrinsic factors.
Therefore, even if the exact physiological response of a species to a
pesticide can be predicted this will not necessarily demonstrate
whether the species will increase or decrease as a result of the
application of the chemical.
3. The pesticide will impinge at all levels of organization: at levels
of the cell and the organ, and a t the levels of ihe individual, the
population and the ecosystem. Therefore the most adequate explanation of pesticide effects consists of a synthesis of information