COST OF PRODUCING APPLES IN YAKIMA VALLEY. 



39 



THINNING. 



Thinn in g is an annual practice of all orchardists visited in the 

 valley. (See fig. 7.) Usually it is begun during the month of June, 

 shortly after what is known as the "June drop. " The time required 

 for this operation varies much, depending on the size of the crop, 

 the variety, age, and size of tree, and the method adopted in thinning. 



The usual practice is to thin so that the fruit is well distributed 

 over the tree. No set rule can be given, although the growers aim 

 to leave only one apple in a place, partly for the reason that where 

 two apples touch each other a favorite opportunity is offered for the 

 codling-moth larva to work. The amount of thinning depends to a 



Fig. 7.— Thinning a 7-year-old Winesap tree in the Zillah district. Alfalfa is used as an intercrop and 

 mulch crop here. Note the size of tree for its age. 



considerable extent upon the season. If the crop is light and the 

 apples are borne in clusters, two apples sometimes are left in a place; 

 but with a heavy crop and varieties which tend to small size, many 

 make a practice of thinning to 6 or 8 inches. Needless to say, with 

 a large crop the work of thinning will be doubled or even trebled. 

 Many times it is necessary to do more than one thinning during the 

 season, this being especially true of red varieties. Practically all 

 thinning throughout the valley is done with thinning shears. The 

 trees are of such size and age that most of the work may be done from 

 the ground or from an 8- to 10-foot stepladder. 



The amount of thinning is governed not only by the size of the 

 crop but by the amount of pruning that is done. The cost of thinning 

 operations in the valley is 18.38 per cent of the total gross labor cost 



