THE DISEASES OF FRUITS. 219 



There are three points of attack, namely, the flowers, the 

 opening leafbuds, and, thirdly, any exposed portion of tissue 

 upon the main branches and stem, and as a result there are 

 as many varieties of fire blight in common speech. However, 

 the " flower blight," " twig blight," and " body blight" are all 

 caused by the same organism and differ only in the place 

 of invasion. The blight of the apple, previously mentioned, 

 is chiefly of the blossom sort and rarely more than a few 

 inches of the stem bearing the flowers with its leaves becomes 

 killed by the germs. Occasionally all the blossoms are de- 

 stroyed and the crop is lost, but as frequently the result is a 

 natural thinning of the fruit before it forms and no great harm 

 is done. 



With the pear the blight is most at home, and here the 

 whole tree may be invaded and destroyed. Some varieties are 

 more susceptible than others, but some that were considered 

 immune are now badly afflicted. In setting out new orchards 

 the fruit-grower should consider among the most important 

 things the liability of the variety to the fire blight. 



In connection with this fatal disease there is not much to 

 show in a picture ; the blighted tree is unmistakable. The 

 ^erms themselves are exceedingly small, and each organism 

 is provided with whiplash-like motile organs, by means of 

 which they are usually in motion. 



Remedies. Mr. Waite, of the Department of Agriculture, 

 who has made a prolonged study of this subject, is of the 

 opinion that the germs live over winter in the margins of 

 blighted places, where the diseased cambium joins that which 

 is healthy, and not in the dead twigs or the soil. While 

 blighted twigs should be removed whenever seen, autumn is 

 the best season to go over the orchard in a searching manner 

 and remove all of the blight. The branches should be cut off 

 a foot or more below the least sign of the blight or else it will 

 hold over in the stump and the neighboring new shoots may 

 be killed the next season. The greatest difficulty in removing 

 the germs in a tree is when there is the so-called body blight, 

 but in many instances this dies out of its own accord. 



It is evident from the nature of the disease that spraying 

 as for ordinary fungi will be of very little avail. If the inocu- 

 lation is chiefly through the flower it comes at a time when 



