238 JOURNAL OF THE ROYAL HORTICULTURAL SOCIETY. 



THE POLLINATION AND SETTING OP ERUIT BLOSSOMS 

 AND THEIR INSECT VISITORS. 



By Cecil H. Hooper, M.R.A.C. 



[Read July 30, 1912 ; Mr. F. J. Chittenden in the Chair.] 



Essentials for successful fruit-growing, such as good varieties, suit- 

 able soil, good cultivation, and the maintenance of the crop free from 

 disease and insect pests, have long been carefully studied and practised, 

 but the problems connected with the pollination and setting of fruit, 

 which are of equal importance, have been less studied, and there is 

 probably still far more to find out concerning them than is already 

 known. Whilst frost at blossoming time is often calamitous to our 

 fruit crops, especially if the blossoms are moist, yet, like the household 

 cat, 'frost is in some cases blamed for damage of which it is not the 

 cause. 



Thus in some kinds of cherry a fungus attacks and causes the 

 shrivelling up of the flowers, a result often wrongly attributed to frost, 

 and frost is often blamed for the results of lack of efficient pollination. 



The best natural safeguard to modify damage by frost is to ensure 

 the blossoms being pollinated soon after they open, as it is an ascer- 

 tained fact that a pollinated blossom is less susceptible to injury by 

 frost than one that is awaiting pollination. Pollination in fruits is 

 found to be almost entirely due to insects, wind, except with nuts, 

 transferring pollen far less than one would naturally suspect. 



Of course in order to have fruit there must be flowers, but I do not 

 propose to go into the question here of how to persuade a barren tree 

 to produce flowers. 



Some varieties, although they blossom well, set very little fruit. 

 Why this is, is the nut to crack. The cause does not appear to be due 

 to any defect in the structure of the flowers, for the pollen grains and 

 the stigmas are usually perfect. 



Method of Pollinuiion. 



The siraivberry in the field or garden appears to be able to set fruit 

 well almost without insects, and probably in this fruit the wind carries 

 the pollen over the flower. 



The raspberry and loganberry will set some fruit with insects 

 excluded; but the fruit is usually imperfect in shape, especially in the 

 raspberry, and inferior to where it is open to the visits of insects. Bees 

 are very fond of raspberries and still more fond of loganberries. 



In gooseberry, red, white, and black currants, the pollen is globular 

 and glutinous (like tapioca) ; wind cannot carry it, so it is necessary in 

 order to have fruit that insects should transfer the pollen from the 

 anthers to the stigmas. 



