540 FUNDAMENTALS OF FRUIT PRODUCTION 



carrying insects the common honey bee is probably the most important 

 for the fruit grower. Its importance is such that the presence of an 

 ample number should be insured during the blossoming season. In 

 some of the cherry growing sections of the Pacific Northwest growers 

 make a practice of securing colonies of bees from apiarists to place in 

 their orchards during blossoming and they find that the rental they 

 pay yields them a higher rate of interest on their investment than any 

 other item in their cost of production. No hard and fast rules can be 

 laid down regarding the number of colonies necessary for effective pol- 

 lination in an orchard of a given size. Much depends on the size of the 

 trees, their profusion of bloom and the number of hours of favorable 

 weather for pollination during their flowering season and the presence 

 or absence of other pollen-carrying agents. Ordinarily one colony of 

 bees to each 1 or 2 acres of orchard, depending on conditions, will 

 produce satisfactory results and sometimes they will take care of a 

 considerably larger acreage. 



It is often assumed that perfect flowered and self fruitful varieties 

 require no outside agent for the transfer of pollen from stamen to stigma. 

 In other words, the self fruitful variety is assumed to be autogamous. 

 This is often the case, at least to a certain extent, However, it has 

 been found in California that Imperial prune trees from which bees were 

 excluded during the blossoming season set only 0.34 per cent, of their 

 blossoms, while trees of the same variety accessible to bees but protected 

 from cross pollination from other varieties set 3.02 per cent.''^ In 

 the French prune 19 per cent, of the blossoms matured fruit where bees 

 visited them, while only 0.43 per cent, matured fruit where the bees were 

 excluded. Conditions may be quite different in other fruits or in other 

 self fruitful varieties of the plum, but in the absence of definite knowl- 

 edge that the varieties he is growing are both self fruitful and autogamous 

 the grower should make adequate provision for pollen transfer. 



The Fruit Setting Habits of Different Fruits. — In the preceding 

 discussion of the factors influencing the setting of fruit most deciduous 

 fruit species have been mentioned along with certain others. Following 

 are summarized statements of the more important fruit setting character- 

 istics of the common fruits. 



Apple. — The flowers of the apple are true hermaphrodites. Occa- 

 sionally defective pistils are found and generally a portion of the pollen 

 grains are defective, though apparently all varieties mature a certain 

 amount of good pollen. i° The percentage, however, varies with environ- 

 mental conditions. Many varieties are self fruitful, many others are 

 self barren or partly so. Lewis and Vincent^^ reported about 70 per cent, 

 of the varieties studied as self barren in Oregon; Gowen^^ found about 

 63 per cent, completely self barren and only 13 per cent, completely self 

 fruitful in Maine and Hooper^^ reported about two-thirds of the varieties 



