260 FARM FRIENDS AND FARM FOES 



Drops of viscid liquid are commonly found along the 

 margin of the diseased areas of the bark. These are 

 swarming with the germs of the Bacillus. Bees and other 

 insects are attracted to these drops, sucking them up and 

 getting myriads of microbes upon their feet and mouth 

 parts. 



Many bacteria multiply rapidly in sweet, jelly like liquids. 

 Such a liquid is found in the nectar cup at the base of the 

 pear blossom, and to a less extent on the end of the pistil 

 of the same flower. Should a bee 

 visit a diseased tree and get some 

 of the blight microbes upon its 

 feet or mouth parts, and then visit 

 the blossoms of a healthy tree, some 

 of these germs would probably be 

 introduced upon the nectar of the 

 latter. 



CLAW FROM BEE'S FOOT When thus P laced in a position 

 WITH BLIGHT BACTERIA favorable to growth, the bacteria 

 TO SHOW THE RELATIVE multiply rap idly, and follow down 

 SIZE : HIGHLY MAGNIFIED r J \ 



through the stalk of the flower to 



the twig. Here they continue to develop, and soon may 

 spread downward through the branch. As far as they go 

 they kill the tissues, causing blossoms, leaves, and twigs 

 to turn black. 



The germs may also be introduced to new trees through 

 breaks in the bark or by the gnawings of insects. The 

 disease is more severe in trees that grow rapidly than in 

 those that grow slowly. Consequently cultural methods 

 that induce rapid growth are to be avoided. The prompt 

 cutting off and burning of all affected branches, taking 

 care that the germs are not distributed by saw, knife, or 

 shears, is the most effectual remedy. 



