PESTS AN ' !DES 



well as the "cosmetic" pests and 

 others, needs changing. Unrealistic 

 marketing standards, consumer at- 

 titudes, government regulations, and 

 so forth perpetuate an unrealistic 

 demand for totally unblemished, in- 

 sect-free produce; this demand can 

 greatly complicate an otherwise real- 

 istic solution which could provide 

 high-quality produce and high yields 

 at reasonable cost. 



The Status of Our Knowledge 



The final result of the approach 

 described above should be an en- 

 lightened systems-analysis approach 

 to decisions on strategy and tactics 

 of pest control, with due allowances 

 (based on value judgments that so- 

 ciety will have to make) for the im- 

 pact each measure might have, not 

 only for the benefit/cost relationship 

 (to the grower and the consumer), 

 but for the quality of the environ- 

 ment (health, wildlife, aesthetic, etc.). 



Research Needs — We need mod- 

 els for depicting the control of a com- 

 plex of pests on a crop. The modeling 

 of a single pest population in the field 

 has progressed rather far in a few 

 instances. There is, for example, a 

 model of a laboratory population of 

 a grain insect and its parasite over 23 

 generations, with remarkably good 

 prediction for the whole 23 genera- 

 tions — not just generation by genera- 

 tion. However, this is a simple two- 

 species system in a simple, constant 

 environment. In the field, we need 

 to gain similar insights into the whole 

 environmental complex (biotic and 

 abiotic), especially the natural-enemy 

 performances relative to the climatic 

 regime, the key pest species, and the 

 possible influences of given pesticides 

 on them (and on ones keeping the 

 innocuous species under control). We 

 also need better knowledge of the 

 phenology of the crop and cropping 

 practices relative to the pests. We 

 have only the roughest information 

 on the economic- injury levels for 

 any pest. Of the few we have studied, 

 the numbers of insects required to 



cause economic injury are much 

 greater than previously considered. 

 This is prerequisite to using pesti- 

 cides wisely or in not using them and 

 relying more on natural controls or 

 cultural measures. 



We need much greater emphasis 

 on means of augmenting the value 

 of natural enemies. Only a beginning 

 has been made relative to use of 

 strategic releases of both pest and 

 enemy species, adding supplemental 

 foods or alternate hosts for enemies 

 in the environment (or nesting sites 

 for avian predators of insects), or 

 using special strains or genotypes of 

 a natural enemy species. The intro- 

 duction of new natural enemies is a 

 vast, largely untapped resource. The 

 hesitancy in doing so, based on 

 theoretical considerations, is refuted 

 by the record of over seventy years; 

 moreover, new theory confirms past 

 policy and speaks for much wider 

 use of new introductions. 



The main reason why more biolog- 

 ical control has not been accom- 

 plished is that vastly too large a por- 

 tion of available effort has gone into 

 work on pesticides in the area of 

 single-minded pesticide-use technol- 

 ogy. A disproportionate amount has 

 also gone into the development of 

 new ideas (e.g., use of releases of 

 sterile insects) that have succeeded 

 only to a very limited degree and 

 and do not offer prospects for wide- 

 scale commercial solutions. A record 

 of some 70 cases of complete biologi- 

 cal control and 250 with at least par- 

 tial success for the world is a for- 

 midable achievement in the light of 

 the effort that has been made on 

 biological control. 



Economic and Political Considera- 

 tions — The pesticides that have been 

 developed are broad-spectrum ones, 

 which is natural since the industry has 

 been motivated by profit. Only token 

 consideration has been given to other 

 aspects (but more so relative to human 

 health). What is needed are pesti- 

 cides with selective activity — i.e., 



which act on a group of pe 

 with little effect on key natural i 

 groups. It is said to cost from t 

 million to $15 million to develop a 

 pesticide and market it. Many more 

 pesticides would be required for the 

 new technology, and sales of each 

 would be limited. The market price 

 would be high. The public must de- 

 cide if it wants the less pollutive tech- 

 nology badly enough to pay the price 

 in some form of subsidy to develop 

 these materials. Actually, such mate- 

 rials could be nearly self-supporting, 

 since the grower could afford a higher 

 price for them if his total usage of 

 pesticides is thereby greatly reduced. 



Use of resistant hosts has been use- 

 ful in many instances and will be 

 again, but superimposing a pest-re- 

 sistance requirement on top of the 

 already staggering problems in devel- 

 oping high-yielding, good quality, 

 marketable cultigens means that this 

 solution is not likely to be a general 

 one. 



Training Advisers — Lastly, we 

 need to change our whole system of 

 pest-control advisement. In the past 

 it has been based to a large extent on 

 profit from sales. The ecologically un- 

 trained, or even the ecologically an- 

 tagonistic, have often been used as 

 salesmen. There has been great pres- 

 sure on them to sell. They are the 

 closest "advisers" to the growers, who 

 in many cases have relied on them 

 heavily. Excessive concentration on 

 sales and too little attention to need 

 and consequences has led to the cur- 

 rent situation. 



What is needed is a corps of well- 

 trained professionals who sell their 

 advice — i.e., advice not to treat as 

 well as to treat — but not the pesticide 

 itself. Thus, the system of advising 

 should be separated from profit from 

 sales. Since pesticides constitute a 

 poisonous factor in our environment, 

 reaching beyond the confines of the 

 area treated, it seems necessary that 

 society set up such a safeguard, as it 

 has long since in the dispensing of 



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