December, 1958 



Decker: Economic Entomology 



109 



these measures were only partially eft'ec- 

 ri\e, and a large percentage of the apples 

 harvested showed insect damage. In fact, 

 the situation was so bad that the fruit 

 judges at county fairs protested the ad- 

 mission of fruit damaged by codling moth, 

 and eventually a rule was passed that the 

 unmistakable evidence of codling moth 

 damage or the presence of San Jose scale 

 disqualified a fruit for competition. In- 

 secticides did not come into the picture 

 until after the value of Paris green had 

 been established for the control of the 

 Colorado potato beetle and a number of 

 other pests. 



In his third report as State Entomolo- 

 gist, Le Baron (1873:172) recommended 

 only cultural practices for control of the 

 codling moth : 



PRACTICAL TREATMENT. 



This may be reduced to the four following 

 heads: 



1st. Destroying the insects in their winter 

 quarters. 



2d. Picking the wormy apples from the 

 trees. 



3d. Gathering the wormy apples from the 

 ground, or letting swine and sheep have the 

 range of the orchard. 



4th. Entrapping the w^orms in bands and 

 other contrivances. 



To which may be added the help to be de- 

 rived from their natural enemies. 



In his previous report, Le Baron 

 (1872:116) had mentioned the use of 

 Paris green to control cankerworms on 

 apple, and this may in part have led to 

 the subsequent work by Forbes and oth- 

 ers for control of codling moth on apple. 



We find but few references to trials 

 with Paris green on crops in 1867 and the 

 following decade. In 1880, however, with 

 repeated warnings that suitable precau- 

 tions must be observed, large-scale testing 

 of Paris green and its companion, London 

 purple, got under way. After 2 years 

 (1885-1886) of experimentation, Forbes 

 (1889:15) concluded: 



The experiments above described seem to 

 me to prove that at least seventy per cent of 

 the loss commonly suffered by the fruit grower 

 from the ravages of the codling moth or apple 

 worm may be prevented at a nominal expense, 

 or, practically, in the long run, at no expense 

 at all, by thoroughly applying Paris green in a 

 spray with water, once or twice in early 

 spring, as soon as the fruit is fairly set, and 

 not so late as the time when the growing 

 apple turns downward on the stem. 



He presented data showing that, in 



1885, 68 per cent of the unsprayed apples 

 were wormy, whereas only 21 per cent of 

 the sprayed apples were wormy, and, in 



1886, 40 per cent of the unsprayed apples 

 were wormy and 12 per cent of the sprayed 

 fruit. When lead arsenate became avail- 

 able about 1895, entomologists began ex- 

 perimenting with it, and for the next 30 

 to 40 years practically all codling moth 

 research centered around attempts to 

 improve formulations and spray sched- 

 ules involving the use of this chemical. 

 Between 1915 and 1918, in seven sep- 

 arate studies, Illinois entomologists found 

 that in unsprayed blocks fruit ranged 

 from 9 to 84 per cent wormy and aver- 

 aged 45 per cent wormy, whereas in the 

 blocks sprayed with improved lead arse- 

 nate formulations the fruit ranged from 

 1 to 20 per cent wormy and averaged 4.4 

 per cent wormy. 



\Vith what appeared to be a satisfac- 

 tory control measure working reasonably 

 well year after year, entomologists and 

 fruit growers alike became more or less 

 complacent, only to be shocked by a dou- 

 ble-barrelled attack. The codling moth 

 began to show evidences of resistance to 

 arsenical sprays, and, as dosage rates and 

 numbers of applications were increased, 

 the United States Food and Drug Ad- 

 ministration began to bear down on lead 

 and arsenic tolerances. The next three 

 decades might be characterized as a pe- 

 riod of mad scramble for cover. Attempts 

 were made to find ( 1 ) ways to remove 

 spray residues, (2) suitable substitute 

 materials, (3) ways to synergize insecti- 

 cidal action without increasing residues, 

 and (4) better sanitation and other non- 

 chemical procedures. Research did well 

 to hold its own, during this critical pe- 

 riod, until DDT came into the picture at 

 the close of World Wai II. The success 

 of DDT in controlling the codling moth 

 was spectacular, and within 2 years the 

 growers' clamor for more work on codling 

 moth control faded. 



A review of research data and the re- 

 sults of harvest surveys made the past 3 

 years show that now 33 to 94 per cent of 

 the fruit in unsprayed apple orchards is 

 wormy, approximately the same percent- 

 ages as in the 1860's, 1880's, and the sec- 

 ond decade of the present century. In 



