THE PEAR BLIGHT 3Q3 



The very exuberance of the pear in California seems to increase 

 the virulence of the blight. The long growing season with its con- 

 tinual production of new soft tissue, the unseasonable bloom which 

 attracts bees to bring new supplies of blight germs, the break 

 of new shoots from root, trunk and main branches all these make 

 the tree subject to repeated renewals of the disease in its most 

 vulnerable parts. How far growth can be repressed by scant cul- 

 tivation or by summer pruning; how far suppression of later shoots 

 and blooms is practicable and whether the tree can be depleted 

 so that it can only make fair sized fruit and no surplus soft tissue 

 for blight invasion all these are cultural problems which make 

 pear growing very interesting to the enquiring mind. A Sonoma 

 grower suggests that pruning may be used to control pear blight 

 in the following manner : It is the natural tendency of the pear 

 and apple while young to form fruiting spurs upon the body and 

 larger branches of the tree. These fruiting spurs produce blos- 

 soms from year to year, which are in turn as liable to be visited 

 by bees or other insects carrying the destructive spores of the 

 disease as are the blossoms at the ends of the branches. It is 

 evident, therefore, that a blossom situated upon the body or 

 larger branches of a tree, becoming infected, would communicate 

 the disease directly to the framework of the tree, with the result 

 that it would be fatally injured; but if these fruiting spurs are all 

 removed from the body and larger branches by pruning, the possi- 

 bilities of infection in this way are overcome. The available means 

 of gaining entrance to the tree by this parasite is confined to the 

 smaller branches, which if affected can be cut away without 

 severely injuring or disfiguring the tree. All suckers at the base 

 of the tree should be removed at 'the point where they emerge 

 from the trunk or the roots as they favor the entrance of blight 

 to the root. The Leconte root is being used because of its resist- 

 ance. 



The scab fungus which seriously affects some varieties, and 

 notably the Winter Nelis, in the Coast region, is identical with the 

 scab of the apple and will be mentioned in the chapter on tree 

 diseases. Because Of the liability of the Winter Nelis, to this dis- 

 ease, and because of its irregular bearing in the coast region, there 

 have been many trees grafted over into varieties better suited to 

 coast conditions. The Beurre Clairgeau, because of its health, 

 prolific bearing, and acceptability to shippers, was largely intro- 

 duced in this way, but it has not sold as well as expected. Ordi- 

 nary top grafting succeeds admirably with the pear. Clapp's Fav- 

 orite and other varieties have also been worked upon Winter Nelis 

 but they are apt to be more susceptible to blight than Winter 

 Nelis so this old practice is now of less value than formerly. 



