1044 THE FRUIT INDUSTRY ix XEW YORK STATE 



Even on trees in the most susceptible condition, however, no 

 blight would occur unless there were present a source of infec- 

 tion in the form of infected tissues. Such infected tissues need 

 not necessarily be in the same orchard and, indeed, may be a 

 considerable distance away, but the nearer and more abundant 

 they are, the more chance there is that new infections will take 

 place. When the trees are in a susceptible condition, there is 

 greater danger of new infections occurring, if the hold-over can- 

 kers are oozing, than at any other time. The oozing must take 

 place at the time the trees are in bloom if blossom blight is to 

 occur. As stated earlier, the oozing occurs during, or shortly 

 following, warm moist weather. After the ooze becomes dry so 

 as not to be sticky, it is not so likely to become a source of 

 infection. 



Again, the trees may be in a susceptible condition and the 

 sources of infection may be abundant, yet no blight occurs unless 

 there is an agent to transport the germ and introduce it into 

 the susceptible plant. These agents, however, are usually abun- 

 dant both in the form of insects and of man with pruning tools. 



Methods of Control 



With these thoughts in mind we shall proceed to an outline of 

 control measures. The first step to be taken in controlling fire 

 blight is the removal (during the dormant season) of sources of 

 infection so far as possible. Not only should all infected 

 branches, twigs, water sprouts, and hold-over cankers be removed, 

 but badly infected trees should be cut down. Old hawthorne and 

 wild crab-apple trees along fence rows and in pastures frequently 

 harbor blight, and should therefore be destroyed. All affected 

 portions cut away should be burned, although it is not necessary 

 at this season to be particular about small twigs that can be 

 plowed under. 



In removing blighted twigs and limbs, the cut should be made 

 several inches below the line separating diseased and healthy 

 bark. In removing cankers on body or limbs, the operator should 

 make % clean spindle-shaped cut with a heavy sharp knife about 

 two or three inches from the. margin of canker at the sides, and 

 four or five inches away at top and bottom. Care should be taken 





