16 



BULLETIN 938, U. S. DEPARTMENT OF AGRICULTURE. 



collected once a Aveek and examined for codling-moth injury, and 

 at picking time the picked fruit" was also examined. The results of 

 these examinations are given in Table V. 



Table V. — Codling moth injury as shown by examination of both fallen and 

 picked fruit from experimental plats at Benton Harbor, Mich., 1917. 





Xumber of applications and brief 

 formula of each. 



Fruit record. 



Xo. 



of 



plat. 



Number of larval en- 

 trances at — 



Number 



of wormy 



apples. 



Total 

 number 

 of apples 

 exam- 

 ined. 



Percent- 

 age of 

 total 

 number 

 of apples 





Calyx. 



Side. 



Stem. 



free from 

 worms. 



1 



1 application of lime-sulphur and 3 

 applications of lime-sulphur + 1 

 pound arsenate of lead to 50 gallons 



191 

 559 



40 

 2,032 



277 

 002 



195 



007 



14 

 71 



4 

 93 



336 

 1,249 



231 

 2,484 



6,543 

 9,924 



2,949 

 6,060 



94.71 



o 



1 application of lime-sulphur and 3 

 applications of nicotine sulphate 

 l:800+soap 



87.41 



3 



1 application of lime-sulphur and 3 

 applications of nicotine sulphate 

 l:S00+soap+0.5 pound of arsenate 



92.15 



4 



1 application of lime-sulphur (check) . . 



59.00 



Reference to Table V shows that nicotine sulphate (plat No. 2) 

 gave a control of only 87.41 per cent, while arsenate of lead (plat 

 No. 1) gave a control of 94.71 per cent. There is thus seen to be 

 no practical advantage in combining arsenate of lead with nicotine 

 sulphate in sprays designed to control the codling moth (plats Nos. 

 1 and 3). 



EXPERIMENTS PERFORMED AT GRAND JUNCTION, COLO. 



Experiments similar to the preceding were also performed at 

 Grand Junction, Colo. Of the 12 plats sprayed, only 2 were sprayed 

 with nicotine sulphate, but since the results obtained using arsenate 

 of lead vary so greatly, the data from 4 of the latter plats are given 

 in Table VI, so that the results from the plat sprayed with nicotine 

 sulphate may be compared with those from the plats sprayed with 

 arsenate of lead alone and also with the results from the plat sprayed 

 with arsenate of lead and nicotine sulphate combined. In plats on 

 which it was applied (i. e., all except plats Nos. 10, 14, and 15), 

 the calyx application was made with a Bordeaux type of nozzle 

 which delivered a fairty coarse and driving spray; a mist type of 

 nozzle was used for all subsequent applications. With this exception 

 the same spraying equipment was used for all plats except the checks. 



At various times throughout the growing season and at harvest 

 time the apples on eight trees in each plat (four in each of the two 

 check plats) were examined; the results of these examinations, to- 

 gether with the treatment of the several plats, are given in Table VI. 



