THE THINNING OF FRUIT 117 



the June drop period to nearly 67 per cent at the market 

 ripe period. 



"These figures, therefore, furnish a scientific basis for 

 early thiiming, also for the frequent observation that the 

 development of a large number of pits makes a heavy de- 

 mand for plant food." 



Experience dictates the item listed mider 3 and it re- 

 quires no further explanation. 



Some . writers suggest that the trees should be thinned 

 twice or thrice, the first time after the June drop, the second 

 about the middle of August, and the third about three weeks 

 before picking, because the operator is not likely to thin 

 sufficiently the first time over the trees. Doubtless it will 

 seem necessary, especially to the begimier, to go over the 

 trees at least twice in order to secure best results, but this 

 is not likely to be possible on large scale orcharding. 



With some early varieties such as the Yellow Transpar- 

 ent, it may be desirable to allow all the fruits to develop for 

 a while and gradually thin the crop by making several pick- 

 ings. The apples can be sold when quite small as this va- 

 riety is merchantable when only a third or half grown. 



103. The June drop referred to above is a natural ab- 

 scission of the fruit which occurs at the time the permanent 

 fruits are setting. That is, many fruits will start to develop 

 and later fall. The explanation usually offered for this oc- 

 currence is that the fruit is imperfectly pollinated; or it has 

 been injured by insect or fungus disease; or the struggle for 

 existence that may operate against a portion of the fruits 

 in a cluster. Often it is greatly increased by adverse 

 weather conditions at bloom time. Usually the central blos- 

 som in a cluster opens first and when the fruit is set remains 

 on the tree. 



Peach- and plum-growers need no further evidence than 

 they already possess that the curculio is responsible for a 



