170 DISEASES OF FRUIT TREES 



be found some distance below where there is any outward sign 

 of the disease. It winters over in the old, diseased tissues and is 

 spread in the spring to the growing shoots, largely through the 

 instrumentality of insects, particularly bees. Bearing apple 

 trees may often be seen with one-quarter of the fruit spurs dead, 

 and in every spur the infestation came through the blossoms, 

 doubtless having been carried by the bees in their visits to the 

 blossoms. 



There is a marked difference in the susceptibility of varieties, 

 the "Wealthy and Khode Island Greening, among apples, and 

 the Bartlett, Clapp and Flemish Beauty, among pears, being 

 especially liable to attack, while the Mclntosh and Baldwin 

 apples and the Anjou and Seckel pears are much less so. 



The Eemedy. The disease cannot be influenced by spraying. 

 The only satisfactory remedy is to cut out the diseased parts, 

 and the best time to do this is in the autumn. If all the dis- 

 eased areas can be cut out and burned during the dormant 

 season there will be no outbreak in the spring. Of course this 

 cannot be done, but systematic effort will go a long way towards 

 it. If the work can be done in the autumn before the leaves 

 fall, so much the better, as the affected areas are more easily 

 located then. The diseased shoots should also be cut during 

 the growing season, though this is a less efficient time than 

 the other. Great care should be taken to get well below the 

 diseased portion in this cutting so as to be sure that all the 

 bacteria are removed. 



The shears or knife with which the cutting is done should be 

 disinfected after every cut to prevent any germs being carried 

 to healthy tissue; otherwise this cutting may really spread the 

 disease from branch to branch. For this disinfecting a solu- 

 tion of corrosive sublimate is used (1 part to 1000). A cloth 

 or sponge dipped in this may be used to wipe the shears, or it 

 may be carried in a can and the shears dipped into it. In the 

 winter work all affected parts which are cut out should be 

 gathered up and burned. This is not so important in summer 

 work, since the parts removed are soft and soon dry up and 

 kill the bacteria. 



