122 PEACH LEAF CUEL*. ITS NATURE AND TREATMENT. 



the fruit is for the most part nourished by the foliage of the branch 

 which bears it, and hence if the disease is not equally distributed the 

 foliage will be unequally distributed and the fruit unequally nourished. 

 One portion of a tree may have an excess of fruit, even to the break- 

 ing of liml)s, while another portion shows a deficiency. Besides the 

 unequal thinning of fruit on different portions of a tree, arising from 

 the unequal action of curl over the tree as a whole, there will also 

 appear an unequal thinning of the fruit of individual branches. In 

 this respect, one of the prime objects of hand thijining, the equalizing of 

 the fruit distribution upon the branches, is lost when the thinning is 

 caused by curl. Such fruit as remains upon the curl-thinned ])ranches 

 is apt to be largely toward the ends of the limbs. 



The statements here made respecting the local action of the disease 

 and the local nourishing of the fruit upon a limb or portion of a tree, 

 are known to be correct, and have been established by a series of care- 

 fully conducted experiments on sprayed halves of trees. The details and 

 results of this work are given in the concluding section of this chapter. 



COST OP PICKING PEACHES. 



When considering the picking and sorting of peaches from sprayed 

 and unsprayed trees a marked difference is noted in cost in favor of 

 those sprayed. In the Rio Bonito orchard, where our experimental 

 work was prosecuted, it has cost the proprietors $1 per ton to pick 

 fruit from fully loaded sprayed trees. In contrast to this the cost 

 of picking and sorting the fruit of the unsprayed trees just north of 

 the experiment block, in the summer of 1895, was $3 per ton. This 

 was on account of the scattered condition of the fruit on these trees, 

 which were affected by curl in the spring like the control trees of the 

 experiment block. This cost per ton was calculated with wages at ^1 

 per day, the men boarding themselves, and where one sorter to five 

 pickers was employed. We have here a difference of $3 per ton in the 

 cost of picking and sorting fruit from sprayed and unsprayed trees. 

 This added expense on unsprayed trees arises, of course, through the 

 necessity of picking over a greater expanse of tree and orchard surface 

 to obtain a given amount of fruit. It is believed that in this single 

 item of picking the fruit enough is saved to more than cover the expense 

 of spraying the trees and thinning the fruit. 



THE LOCAL ACTION OF CURL ON FOLIAGE AND FRUIT. 



RECORDS OP TREES SPRAYED ON ONE SIDE. 



The study of the habits of Exoascus deformans and its influence upon 

 its host led to the following investigation into the localization of the 

 parasite upon the tree and its local rather than general effects. 



