39 



ever, that the finer apples are more hable to attack than the coarser 

 kinds.) We have left, then, only the difference in abundance of 

 apples upon these two trees to account for the extremely different 

 ratios of insect injury. It would seem that each tree in the orchard 

 attracts an approximately equal share of codling moths, and that 

 when a tree bears but few apples, a large percentage of these will 

 be attacked ; while if the apples are numerous, the attack will be 

 less concentrated, and the ratio of injury proportionally diminished. 

 These circumstances will perhaps explain some of the extravagant 

 claims set up for the efficiency of arsenical poisons and other reme- 

 dies as applied to the codling moth and the cnrculios. If I had 

 ventured to report to you upon the strength of a single instance, 

 and if that instance had happened to be the present, I should have 

 asserted no less positively than others the remarkable value of lime 

 as a remedy against the codling moth or apple worm. 



NATUKAL HISTORY OF THE CODLING BIOTH. 



This insect is currently reported to breed twice during the year, 

 one brood of the moths appearing in early spring, and the second 

 in midsummer. The most elaborate observations made upon its life 

 history with which I am acquainted, are those reported by Mr. 

 Charles G. Atkins in the "Agriculture of Maine" for 1883, and as a 

 result of his observations, he concludes that, in the latitude of 

 Maine, at least, only a single brood occurs, distributed in its devel- 

 opment over a considerable part of the season. Our collections and 

 observations made this year snow, however, that in central Illinois 

 the insect is unquestionably two-brooded, the moths of the second 

 brood occurring in July. On the 24th July, at which date nearly 

 1,100 apples injured by the codling moth larvs were examined, not 

 over a dozen of these larvit were found in the fruit. A single 

 pupa also occurred in an apple. Curculio larvae, it may be worth 

 while to note, were at this time decidedly abundant. On the 31st 

 July, again, no mature larvte whatever were found, but a few very 

 small ones were detected at the blossom end of the apple, — evidently 

 young of the second brood. By August 7 the average length of forty 

 examples removed from the apples, was 7.6 mm. — a little more than 

 one fourth of an inch — while, by the 27th August, the average of 

 twenty examples was 10.1 mm., or about two fifths of an inch. On 

 the 31st of this month, three fourths of the apples injured by the 

 apple worm still contained the larv?e, many of them in the blossom 

 end of the apple, and so small as to be difficult of detection. This 

 circumstance is of interest as showing that the second brood is more 

 numerous than the first, — a reason additional to those already men- 

 tioned why no complete protection to the fruit can be afforded by 

 spraying only early in the season. 



CONCLUSION. 



And now, in conclusion, I will give you a summary and brief re- 

 capitulation of the whole matter: 



(1). The investigation was undertaken to test the efficiency of lime 

 and arsenical poisons as insecticides for the codling moth and apple 

 and plum cnrculios in the apple orchard. 



