BULLETIN 158.] [JUNE, 1907 



Ontario Department of Agriculture. 



ONTARIO AGRICULTURAL COLLEGE. 



COMMON INSECTS AFFECTING FRUIT-TREES. 



By C. J. S. Bethune, M.A., D.C.L., Professor of Entomology. 



INTRODUCTION. 



To treat of all the insects affecting- fruit-trees in Ontario would be 

 manifestly impossible within the limits of space assigned to a bulletin, 

 In the following pages, therefore, reference will be made only to those 

 species that are commonly met with, and that are sufficiently abundant 

 year after year, to require attention on the part of the fruit-grower. The 

 remedies prescribed are those that have been found by repeated experi- 

 ments to be the most effective. Much depends, however, upon the care 

 which is exercised in making up and applying the various spraying mix- 

 tures, the time when the work is done and the methods of cultivation 

 which are employed. It is of little use to attempt to kill some insects 

 on a tree or bush, if suitable and convenient hiding places are left for 

 them close by, or if wild plants of a similar character are allowed to serve 

 as breeding places without molestation. Wild cherry-trees, for instance, 

 may often be seen covered with the webs of the Tent-caterpillar in the 

 near neighborhood of orchards and no notice whatever is taken of them, 

 while the fruit-grower labors to clear his trees and wonders that after all 

 his efforts a fresh attack occurs each year. 



The Mountain Ash, a European tree cultivated for its beauty, is 

 often to be found near gardens and orchards. Being closely akin, bo- 

 tanically, to the apple, it is attacked by scale and other dangerous in- 

 sects, and is often a convenient and unsuspected breeding place for many 

 pests of the orchard. It should receive the same treatment as the fruit- 

 trees or else be removed altogether. The Hawthorns are another class 

 of trees akin to the apple, and serve in a similar manner as breeding 

 places for orchard pests ; none should be suffered to grow near the fruit- 

 trees. Both the Wild Cherry and the Wild Plum are also particularly 

 dangerous from the serious fungous diseases to which they are liable, 

 such as the Black-knot, Plum-pockets, Brown-rot and Shot-hole fungus, 

 and which soon spread from them to healthy fruit-trees ; the latter also 

 harbors the Plum Curculio. 



Clean cultivation is of quite as much importance as the application 

 ol remedies. Twigs and branches cut off when pruning should be burnt, 

 all fallen fruit should be gathered up and destroyed, no rubbish of any 



