SUMMER MEETING. 85 



fresh cambium layer. It begins its work at the time of blossoming, 

 the microbes living in the nectar of the blossom, whence they are dis- 

 ttibuted by bees and other insects, so that if a few early blossoms are 

 affected the insects will scatter the disease from flower to flower and 

 tree to tree until it becomes epidemic in the orchard. 



The microbe may enter at the blossom and then run downward on 

 the branches, but in young trees they often enter the tips of growing 

 shoots and then run downward, producing what is sometimes called 

 twig blight. 



The extent of the ravages of this microbe generally are only an 

 inch or two a day, but sometimes reaches as much as one foot. The 

 more rapid the growth of the shoot of the pear twig and the softer its 

 tissues, the greater the injury. So such rapidly growing varieties as 

 Bartlett or Glappa' Fiivorite suffer worse than the hardier, slower 

 growing varieties of Duchess and Keifer. 



Warm, moist weather is favorable to blight ; cool, dry weather 

 unfavorable. Most of the damage done is in a month or two follow- 

 ing bloom, but young trees may be attacked at any time during the 

 summer. 



The signs of the presence of the microbe are the turning of the 

 bark of the extremities dark brown color, and a more or less shrivel- 

 ing of the bark. A few days later the leaves biacken or brown, but 

 remain for some weeks attached to the tree. All the parts of the 

 tree below the point reached by the blight are healthy, no more injury 

 resulting than if the blighted parts had been girdled. 



It has been proved by experiments made by Mr. M. B. Waite, 

 assistant in the United States Department of Agriculture (see Year 

 Book for 1895, page 295), that the microbe lives through the winter in 

 the bark of the tree, and that even freezing winter temperature will 

 not destroy it. On the other hand, very dry weather and cessation of 

 growth in the tree furnishes conditions unfavorable even for their life. 



Such in brief are the conditions which produce the disease. What 

 now are the remedies ? Can anything be introduced into the life of 

 the tree which will be unfavorable to the propagation and destructive 

 ravages of this microbe ! 



In the dozen years or more of pear culture in my own experience, 

 I have used unsparingly the knife. Watching the trees from day to 

 day during spring and summer, I have cut or sawed off the affected 

 part and any branch affected, and at once carried it to the stove and 

 burned it or else built a fire in the garden or orchard for immediate 

 burning, never allowing an affected twig to reiniin 24 hours without 

 cutting. 



