SOCIETY OF NORTHERN ILLINOIS. 319 



only apparent difference between this and stronger solutions 

 being that the former was somewhat less prompt in its action. 

 Weed has also recorded the results of a single observation upon 

 the food of the curculio in the cherry tree, a specimen in con- 

 finement feeding for several days upon the green fruit, gnawing 

 pits in the surface. Practical experiment with London Purple on 

 the scale of orchard practice made in Cobdon, Union County, by 

 Mr. Theodore Goodrich and my brother, Col. H. C. Forbes, were, 

 as reported to me by the latter, thoroughly unsatisfactory, the 

 mixtures used defoliating, or at least badly damaging, the trees, 

 and not protecting the fruit. It is proper to say, however, that 

 these experiments seemed to me to be premature for the peach, 

 since too little has yet been learned with respect to that fruit, of 

 the kind of poison, the times and conditions of application, and 

 the strength of mixture most likely to yield good economic 

 results. 



THE EFFECTS ON THE FRUIT. 



Apple. In addition to the numerous results on the apple 

 hitherto reported I mention two, first a brief account given by 

 the Agricultural Experiment Station of Vermont with respect to 

 the unfavorable result of an experiment with London Purple, 

 Paris Green, and white arsenic, a pound of each to sixty gallons 

 of water, applied when the apples were as large as small marbles, 

 and before they had turned downward on the stem. No benefit 

 was derived from the application of the poison, those which had 

 received it being in some cases worse affected by the apple 

 worm than the check trees not treated. It is probable that this 

 result was due to the late period of application. 



A much more elaborate and thoroughgoing experiment, or 

 series of experiments, was made by Popenoe, of Kansas, last 

 year, as already described under another head. The product of 

 thirty-two Winesap trees, variously sprayed, is brought into com- 

 parison with that of thirteen unsprayed trees of the same variety, 

 with the general result that the greatest saving of apples in any 

 lot was only about half the number which would otherwise have 

 been destroyed, the average saving being about one-fourth of that 

 number. Indeed, the average loss by insect injury on the whole 

 number of trees sprayed with the arsenites amounted to thirty- 

 five per cent, of the entire yield. 



These elaborate and careful experiments bring out interesting 

 facts. While the practice of spraying, he says, "is a most 

 important and valuable method in the protection of early ma- 

 turing fruit, its value for late fruit is lessened by the appear- 

 ance of a second brood of the larva?, which have now the free- 

 dom of the orchard ; and it is after all to these that we are 

 indebted for the greater part of the damage to our winter fruit. 

 The argument follows, that even with the most careful and 



