PART X — ENVIRONMENTAL CONTAMINANTS 



drugs for medicinal purposes. Whole 

 new programs of training pest-control 

 professionals who will do this advis- 

 ing are needed in the universities. 



A General Perspective — It will be 

 necessary that adequate care is taken 

 to assure that the necessary changes 

 in philosophy and methodology are 

 made at each institutional level. The 



old philosophy and methodology have 

 been entrenched for 40 years, and 

 nothing less than extreme action will 

 alter the picture fast enough. 



At the same time, it is wishful 

 thinking to pin hopes on conceptually 

 intriguing new, but generally un- 

 proved, ideas of pest control — e.g., 

 use of sterile insect releases, inunda- 



tive parasite releases, genetic tech- 

 niques, hormones, special wave- 

 lengths, plastic exclusion airdomes, 

 and the like. A planned systems- 

 analysis integration of the long- 

 established techniques of biological 

 and cultural controls, and limited but 

 strategic use of selective chemical 

 controls, offers our best prospect of 

 solutions on a broad scale. 



Pesticides and the Pollution Problem 



In a broad and complete view of 

 pollution of the earth's biosphere, 

 pesticides are a minor element. Never- 

 theless, for certain local environments 

 or for certain endangered species, the 

 pollution from specific pesticides has 

 become a problem worthy of special 

 attention. In our general concern 

 about this pollution and in our re- 

 sponse to other undesirable effects of 

 certain pesticides, it is not rational 

 to condemn all pesticides. Further- 

 more, it is ill-advised to attempt to 

 ban all pesticides (even all persistent 

 pesticides) in the misguided hope that 

 this will protect birds and other wild- 

 life from the effect of man's disrup- 

 tion and pollution of the environment. 

 Even if all pesticide use were stopped, 

 other activities of man would cause 

 broad and sweeping disruptions of 

 his ecosystems and threaten many 

 forms of desirable life on this planet. 



Uses and Limitations of Pesticides 



Pesticides remain, in spite of ad- 

 verse publicity, man's most powerful 

 tool in the management and control 

 of pests. We have no choice, if we 

 insist on even minimal food, health, 

 and comfort, but to control pests. 

 The pesticides developed in the past 

 25 years are effective and economical 

 and can be marshalled quickly to 

 have immediate impact on a pest 

 population — even over a large area. 

 When pest populations approach eco- 

 nomic levels, there is little other than 

 pesticides that we can use to avoid 



damage and which will have the de- 

 sired immediate effect. Hence, it 

 seems clear that pesticides must and 

 will continue to be used in a major 

 way in pest management. 



The disadvantages or limitations 

 of pesticide chemicals are well known. 

 They have been so emphasized in 

 the press, on radio and TV, in politi- 

 cal arenas, and elsewhere that it is 

 now difficult to have a rational dis- 

 cussion that balances the beneficial 

 and the undesirable aspects of pesti- 

 cides. In brief review, the limitations 

 of pesticide usage are as follows: 



1. Selection of pest strains that 

 are not controlled by usual 

 pesticide dosages. 



2. Temporary effects on pest pop- 

 ulations necessitating repeated 

 treatment (often the pest popu- 

 lation quickly returns to a 

 higher level than before treat- 

 ment). 



3. Hazards from residues of the 

 pesticide in the harvested crop. 



4. Outbreaks of secondary pests 

 unleashed by destruction of 

 their natural enemies. 



5. Undesirable effects on nontar- 

 get organisms, including (a) 

 parasites and predators; (b) 

 fish, birds, and other wildlife; 

 (c) honey bees and other nec- 

 essary pollinators; (d) man and 



his domestic animals; and (e) 

 the crop plant. 



o. Direct hazards to man during 

 the application of pesticides 

 and subsequently in the treated 

 area. 



7. Reduction and simplification of 

 the biotic component of the 

 agro-ecosystem. 



Factors Affecting Pesticide Use 



This formidable list makes it nec- 

 essary to re-evaluate carefully the 

 appropriate use of pesticides. It also 

 serves as a basic guide to the im- 

 proved use of pesticides for pest 

 management and control. If we can 

 devise procedures for the use of 

 pesticides which will avoid or mini- 

 mize these disadvantages or com- 

 plications, then we will have devel- 

 oped an improved, perhaps even an 

 ideal, methodology for the efficient 

 and effective use of pesticides. 



Destruction of Natural Enemies — 

 Ecologists concerned with the control 

 of pest insects have for some time 

 been alarmed at ecological disturb- 

 ances in agro-ecosystems engendered 

 by the unwise use of pesticides. 

 These are caused by the unintended 

 destruction of natural enemies, which 

 in turn results in rapid resurgence 

 of the target pest species or a sec- 

 ondary outbreak of an unleashed but 

 formerly innocuous insect. For ex- 



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