EXPERIMENT STATION BULLETINS. 231 



be checked and future productiveness lessened. If a tree is left unthin- 

 ned, particularly if the summer is a dry one, it often attempts to relieve 

 itself by dropping part of the fruits; and, as they are somewhat loosely 

 attached, a heavy wind-storm may strew the ground with the half-grown 

 peaches, oftentimes taking nearly the entire crop. While the trees 

 would have been more likely to retain the fruit had they been 

 thinned, there would also have been a much less serious strain to the 

 tree, as the small number of pits formed would take less mineral food. 

 In some seasons the fruit drops badly soon after it has set, from the 

 effects of curculio, curl, extremes of moisture, or other causes, and for 

 this reason the thinning should be delayed as long as possible without 

 drawing on the trees too much. If done just before the pits begin to 

 harden, as a rule, there will be little loss from dropping after that time. 

 The fruit will be about the size of a natural peach pit, and it will be early 

 enough to avoid a strain to the trees. The time will vary with the season 

 but, as a rule, the 12th to 18th of June will answer in southern Michigan 

 and the 15th to 25th in the northern half of the state. In localities where 

 the rose chafer is troublesome, it will be well to at least delay the final 

 thinning until danger from them is over. In thinning the fruit, no set rule 

 can be given, as it varies with the size and vigor of the tree, the variety, 

 and with the amount (if any) the tree has been headed back. The old 

 rule, when trees were not headed back, was to leave a peach every six inches 

 upon the branches, and it is a safe rule to follow under those conditions, but 

 when the fruit has been partly thinned by heading back it will not answer. 

 . If evenly distributed over the tree, and when the branches are clothed 

 with soft, spur-like branches, it will be well, as a rule, never to leave 

 more than two peaches upon any branch unless it is long and unusu- 

 ally strong, and not to have them under any conditions nearer than four 

 inches from each other. On the other hand, if the side branches are not 

 numerous, and if the shoots are cut back very severely, the distance may 

 be somewhat lessened and the number increased. In thinning, an effort 

 should be made to leave the peaches as evenly distributed as possible, 

 making due allowance for the size and strength of the branches. The 

 larger fruits, and particularly those near the base of the shoots, should be 

 left and the others removed. With a little experience, a tree can be very 

 readily thinned, particularly if it has been well headed back, which, as 

 noted before, will greatly reduce the number of peaches that need to be 

 removed with the hand; and lessening the height renders the operation 

 much easier, as most of the work can be done from the ground. The 

 length of time required to prune a tree varies to such an extent with the 

 size and height of the tree and with the number of fruits to be removed, 

 that no estimate of the expense can be given. It can be safely said, how- 

 ever, that the cost will be several times repaid, to say nothing of the bene- 

 fit to the trees. If when thinning the trees the peaches are thrown into a 

 basket and burned, a great number of curculio will be destroyed and future 

 attacks lessened. When peaches are properly thinned the danger from 

 rot will be dec'reased, as it is a common occurrence to have one diseased 

 peach transmit the rot to all others in contact with it, and when crowded 

 together the rot will be much more likely to appear, than when the fruits 

 are arranged singly. 



MANUEES AND FERTILIZERS. 



So much depends upon the condition and natural fertility of the soil, 

 that only general rules for the application of manures and fertilizers can 



