118 TRANSACTIONS OF THE ILLINOIS 



curculio as our sprayings gave, and especially such prevention of 

 damage to the foliage as we know to be thus afforded, will fully com- 

 pensate for the small expense of the Paris Green application, which, 

 made on a large scale, with suitable apparatus, only once or twice a 

 year, must fall below an average of ten cents a tree. 



I believe, gentlemen, that I have now furnished you proof of 

 the proposition made in the beginning of this paper, viz.: that at 

 least seventy per cent, of the loss commonly suffered by tbe 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. 



Finally, I ought to add that our results are confirmed in general 

 by the only other experiment that I know of, in which the apples 

 were examined witb sufficient care and detail to permit a calculation 

 of ratios of benefit. Last year, at the New York Experiment Sta- 

 tion, Mr. Goff, one of the officers of the station, sprayed three times 

 with Paris Green six trees, and brought them into comparison with 

 four check trees not sprayed. The results of his experiment, as 

 given in the Fourth Annual Report of the New York Agricultural 

 Experiment Station, pp. 218-220, were to the general effect that six- 

 ty-nine per cent, of the apples were effectively poisoned, and that the 

 loss by the codling moth was consequently diminished in that ratio. 

 The whole number of apples examined in the course of his observa- 

 tions was 9,198. 



Mr. Patterson — I sprayed a number of trees last year and found 

 very few codling moths or curculio previous to August, but a late 

 brood took the fruit. I wish to ask Prof. Forbes if it is safe to spray 

 late enough to keep in check these late broods. 



Prof. Forbes — I do not think it safe to spray an orchard after 

 the fruit has turned down, as a sufficient amount of poison might 

 collect in the basin around the stem to endanger life or health. 



Mr. Robison — In your experiments with insecticides for the 

 destruction of codling moth do you notice any appreciable dimijiution 

 of curculio? 



Prof. Forbes — Yes; last year they seemed to decrease about 

 fifty per cent. 



Mr. Wier — My conclusions are that the leaf louse and tarnished 

 plant bug cause greater injury to the apple than the curculio. The 



