POLLINATION IN ORCHARDS. 



I. VARIOUS REASONS WHY FLOWERS DO NOT SET. 



All observing: fruit-o-rowers have seen trees whicli blossom full 

 but do not set a fair amount of fruit ; many have found their orch- 

 ards unpi'ofitable for this reason. It is a practical point to know 

 the causes of this loss and the best way to prevent it. 



Not All the Flowers Can Set Fruit. 



In the first place, but a small percentage of the blossoms set fruit 

 anyway, even in the most favorable seasons and with the most pro- 

 ductive varieties. In blossoming time a Japanese plum tree is a 

 mass of white, carrying scores of flowers on a single branch ; yet 

 scarcely a dozen fruits may set on that twig, and some of those 

 must be removed or the tree will overbear. In the pollination work 

 at Ithaca in 1899, 4,725 untouched blossoms, including apples, pears, 

 plums and apricots, set but 617 fruits. The blossoms counted were 

 those on the tree at large and were used for comparison with the 

 hand crosses. This is about one fruit for every eight blossoms ; yet 

 most of the trees set what would be called a good crop. All of 

 these blossoms were apparently uninjured by the winter, and the 

 weather during the blossoming season was very favorable for the 

 setting of fruit. 



This normal failure in the setting of fruit blossoms may be due to 

 a number of causes ; as poorly nourished fruit buds, lack of polli- 

 nation, or winter injury to the pistils which cannot be seen with the 

 eye alone. It is usually a distinct advantage to the fruit-grower, as 

 it saves thinning. If all plum blossoms set fruit, the expense of 

 thinning would be multiplied many times. Only when the failure 

 of fruit blossoms to set becomes general, does the fruit-grower feel 

 the loss and call for an explanation. 



This wholesale failure in the setting of fruit is often called self- 



363 



