9 



Paris Green, 1885.* 



We begin the discussion with Table I., exhibiting the result of 

 the spraying of two trees eight times with Paris Green in 1885 

 as compared with two other trees selected as checks, — the former 

 bearing 2,419 apples, and the latter 2,964. After spraying three 

 times (June 9, 20, and 30), the apples were first picked up July 16; 

 and already fifty-nine per cent, of those fallen from the check trees 

 were wormy. Passing down the "ratio" column of the check tree, we 

 see at first a slight rise in the ratio of injury, and then a falling 

 off to fifty-eight per cent., July 31, and fifty-five per cent. August 

 7 — the lowest point of the season. This decline coincides with the 

 interval between the first and second broods of the larvae. 



Our notes of July 3i show^ that at this date no full grown larvae 

 whatever were found, and only a few very small ones, at the blos- 

 som end of the apple — evidently the young of the second brood. 



'The averages of injuries to fallen fruit now increased rapidly to 

 September 3, when the last observation was made. At this date 

 the injury to fallen' apples reached eighty-four per cent. The 

 total for all the fallen apples of the season was sixty-five per 

 cent., and that for the picked apples was seventy-five per cent. 

 Finally, adding fallen and harvested apples in one grand 'total, 

 which includes the entire product of the trees, we conclude that 

 sixty- eight per cent, had been infested by this insect. 



These data give us our standard of comparison. Looking now 

 at the columns relating to the poisoned trees, we notice that these 

 suffered much less from the codling moth than the others. Be- 

 ginning at about three per cent., the injury rises to thirteen per 

 cent, falls again to six per cent., and does not rise thereafter 

 above eleven per cent. (August 7). The average irjury for the 

 season to the fallen fruit is nine per cent., and to the picked fruit 31 

 per cent. ; or, to all the apples taken together, twenty-one per cent. 

 Generalizing, we may say that eighty-six per cent, of the apples 

 which would have fallen from codling-moth injuries have been 

 preserved from falling, and that fifty-nine per cent, of the picked 

 apples which would have become wormy remained uninjured; or, 

 taking all the apples from these trees together and comparing 

 with the entire crop of the check trees — assuming, as we evidently 

 have a right to do, that as large a proportion of the fruit on the 

 experimental trees would have been destroyed as on the check 

 trees if the former had not been sprayed, — we shall find that of 

 the apples thus exposed to damage by the codling moth, almost 

 exactly seventy per cent, have been saved by our treatment. 



COMPARISON OF INJURIES, 1885 AND 1886. 



Before passing to the discussion of the experiments of the pres- 

 oiif nsoTi it will be necessary to compare the consequences of 



*.Sonie BliK^it discrepancies between these discussions and those of Bulletin 1 of the office are 

 dne to the fact that these are drawn from the tables, and those from the diagrams there pub- 

 lished. 



