408 



ENCYCLOPEDIA OF PRACTICAL HORTICULTURE 



ment of clarifyiug. carbonating, and heat- 

 ing. 



See Cider. 



H. C. Gore. 

 Of the Bureau of Cliemisti-y. Washingtun. D. C. 



THE POLLI>ATIO> QUESTION 



Every practical orchardist has now 

 come to realize, or if he has not, he 

 should, that one of the most important 

 phases of orcharding is the problem of 

 pollination. It must be considered in se- 

 lecting any variety for planting. The 

 question has been one of scientific interest 

 for many years and unfortunately con- 

 siderable has been written on this sub- 

 ject before definite information was at 

 hand, with the result that many of the 

 recommendations of today must be con- 

 sidered without foundation. 



Too many times one is prone to consider 

 that any lack in the setting of fruit is 

 purely and wholly due to the absence of 

 proper pollination. As a matter of fact 

 there are many causes other than pollina- 

 tion which must be taken into account. 

 Among the first of these we may mention 

 the inability of certain varieties to set 

 fruit, or of certain spurs on the tree to 

 mature fruit from the blossoms which oc- 

 cur on them in the spring. To drop their 

 fruit seems to be as much a character of 

 certain varieties as is the color, flavor, or 

 any other character of the variety. From 

 carefully conducted experiments we must 

 conclude that by no means is all the 

 spring and .June drop to be attributed to 

 lack of pollination. 



Another one of the important causes of 

 dropping of blossoms is the vegetative 

 vigor of the trees. If a tree is growing too 

 vigorously it frequently runs entirely to 

 wood and scarcely produces any blossoms, 

 and the few that it may produce are 

 usually shed very soon after the bloom- 

 ing period is past. The same may be said 

 of trees which are in a very poor condi- 

 tion. While the latter may bloom more 

 profusely than those which are growing 

 vigorously, some blossoms are as incapable 

 of setting fruit as are those on the former. 



Insects and diseases also frequently 



cause the loss of many blooms. Some are 

 destroyed outright by the various diseases, 

 such as scab, anthracnose, or blight and 

 in the case of peaches and plums by the 

 Ijrovvn rot fungus. Many blossoms may be 

 ruined when quite young by attacks of 

 insects. Even some of the blossoms which 

 may be set are later killed by these same 

 causes before they have made any consid- 

 erable size and are frequently shed at the 

 time of the so-called June drop. 



It is almost too well known to need 

 mentioning that rain or snow during the 

 blooming period is the cause of failure 

 of many blossoms. This loss is due to the 

 fact that much of the pollen Is destroyed 

 by rain and the stigmas of the blossoms 

 are injured to such a degree that pol- 

 lination and consequent fertilization is 

 impossible. Of course no fruit is produced 

 vinder such conditions. In this connec- 

 tion, however, it may be well to mention 

 the fact that usually all the blossoms do 

 not come on at the same time and enough 

 may meet with favorable conditions to 

 produce a fair crop. 



One of the most serious climatic condi- 

 tions with which we must contend is 

 frost. Injury from this cause is brought 

 about in two ways: first, by winter freezes 

 and second, by spring frosts. In the form- 

 er instance the fruit buds are either killed 

 outright during the winter, or are injured 

 only to the extent that they are inca- 

 pable of producing fruit. That is. the 

 flowers expand and without careful in- 

 spection appear normal, but on closer ex- 

 amination it is usually found that the pis- 

 tils or heart of the very young fruit has 

 been killed. Injury from late spring 

 frosts is manifested in various ways. The 

 young fruit is subject to injury from the 

 time the fruit buds have opened until 

 the time the fruit is as large as a garden 

 pea or even later. If the frost is very 

 severe the young fruit is generally killed 

 outright as is recognized by a very notice- 

 able blackening a few hours after the 

 frost. In certain instances, generally af- 

 ter pollination has occurred, a light or 

 medium frost does not entirely kill the 

 blossom but seems to allow a certain de- 

 gree of development. Usually in such in- 



