THE PEARS OF NEW YORK III 



tion or preventive except by the most drastic sanitary measures. The 

 other, pear-scab, is always present but not always destructive, although 

 some varieties are always injured by it. The scab, however, is amenable 

 to treatment and at its worst only destroys fruit and foliage, seldom endan- 

 gering the life of the tree. The four or five other diseases of the pear in 

 New York are of minor importance and are readily controlled by the treat- 

 ment necessary to keep in check the scab-fungus. Pear-blight merits 

 attention first. 



Pear-blight is a malignant bacterial disease, very contagious, usually 

 virulent and so terrible in its consequences as to warrant the common name 

 fire-blight. No part of the tree is exempt from destruction by the malign 

 bacterium that causes blight of the pear. Root, trunk, branch, leaf, flower, 

 and fruit are all attacked, turn black and wither under the disease. Few 

 plant diseases produce more disastrous results. The pear competes with 

 the apple in importance in Eiu-ope where blight is unknown. In America 

 it is a poor fourth to the apple, peach, and plum, and takes fourth place 

 instead of second because of the ravages of blight. About the most impor- 

 tant discovery to be made in pomology is a race of blight-resistant pears. 

 Failing in this, if the pear-industry is to grow, or even continue in its present 

 magnitude, blight-resistant stocks must be found. 



The symptoms of pear-blight are so characteristic that the disease 

 cannot be confounded with any other malady or condition of the tree. 

 It appears earliest in the season on the blossoms causing blossom-blight. 

 Attacked by blight, the blossoms wilt, and after the petals fall, fruit and 

 spur show the characteristic blackening of the disease. Blossom-blight 

 may escape the attention of the pear-grower, but twig-blight, a succeed- 

 ing form of the disease, can escape no one who has the sense of sight. No 

 other disease of the pear brings on such palpable destruction to the tree 

 as twig-blight. No other disease causes such comfortless despair to the 

 grower. Twig, branch, or tree, as the case may be, in all affected parts, 

 turns black, the leaves droop, seeming to show the effects of fire. A marked 

 symptom is, if there can be doubt of those given, that the blackened foliage 

 clings most tenaciously to the dead branches. Twig-blight is the most 

 common manifestation of the disease. Another form of the blight appears 

 as a canker on the trunk and large branches — canker-bHght or body- 

 blight. These cankers are dark, smooth, and simken, with definite margins 

 marked by a crevasse in the winter; but as spring comes on the advancing 

 margins become raised and more or less indefinite. Occasionally an opaque 



