background of s ome of thes e men reveals that their entire research program is s upporte d by
the che mical indus try. Their profes s ional pres tige, s ometimes their ve ry jobs depend on the
perpe tuation of che mical methods. Can we the n expect the m to bite the hand that literally
feeds them? B ut k nowi ng their bias , how muc h crede nce can we give to their protes ts that
insecticides are harmless? Amid the general acclaim for chemicals as the principal method of
insect control, minority reports have occasionally been filed by thos e few entomol ogis ts who
have not los t s ight of the fact that they are neither chemis ts nor engineers , but biologists.
F. H. Jacob in England has declared that ‘the activities of many so-called economic
entomol ogis ts would make it appear that they operate in the belief that salvation lies at the
end of a s pray nozzle...that when they have created pro blems of res urgence or res is tance or
mammalian toxicity, the chemist will be ready with another pill. That view is not held
here...Ultimately only the biologist will provide the answers to the bas ic proble ms of pes t
control.’ ‘Economic entomologis ts mus t realize,’ wrote A. D. Pickett of Nova Scotia, ‘that they
are dealing with living things ...their work mus t be more than s imply ins ecticide tes ting or a
ques t for highly des tructive che micals .’ Dr. Pickett himself was a pioneer in the field of working
out s ane methods of ins ect control that take full advantage of the predatory and parasitic
s pecies. The method which he and his ass ociates evolved is today a s hining model but one too
little emulated. Only in the integrated control progra ms developed by s ome California
entomol ogis ts do we find anything compa rable in this country.
Dr. Pickett began his work s ome thi rty-five years ago in the apple orchards of the Annapolis
Valley in Nova Scotia, once one of the mos t concentrate d fruit-growing areas in Canada. At that
time it was believed that insecticides—then inorganic chemicals—would s olve the problems of
ins ect control, that the only tas k was to induce fruit growe rs to follow the rec omme nded
methods. But the rosy picture failed to materialize. Somehow the insects persisted. New
chemicals were added, better s praying equipment was devis ed, and the zeal for s praying
increas ed, but the ins ect problem did not get any better. Then DDT promis ed to ‘obliterate the
nightmare’ of codling moth outbreaks. What actually resulted from its use was an
unprecedented scourge of mites. ‘We move from crisis to crisis, merely tradi ng one problem for
anothe r,’ said Dr. Pickett.
At this point, however, Dr. Pickett and his ass ociates s truck out on a new road ins tead of going
along with other entomologis ts who continued to purs ue the will-o’-the-wis p of the ever more
toxic chemical. Recognizing that they had a s trong ally in nature, they devis ed a progra m that
ma kes ma xi mum use of natural controls and minimum us e of insecticides. Whenever
insecticides are applied only minimum dosages are used—barely enough to control the pes t
without avoidable harm to beneficial species. Proper timing also enters in. Thus, if nicotine
s ulphate is applied before rathe r than after the apple blos s oms turn pink one of the important
predators is s pared, probably becaus e it is s till in the egg stage.
Dr. Pickett uses special care to select chemicals that will do as little harm as possible to insect
paras ites and predators. ‘When we reach the point of us ing DDT, parathion, chlordane, and
othe r new ins ecticides as routine control meas ures in the s ame way we have us ed the inorganic
chemicals in the past, entomologists interested in biological control may as well throw in the
s ponge,’ he s ays. Ins tead of thes e highly toxic, broad-s pectrum ins ecticides , he places chief
reliance on ryania (derived from ground stems of a tropical plant), nicotine sulphate, and lead
arsenate. In certain situations very weak concentrations of DDT or malathion a re us ed (1 or 2
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