INSECTS OF THE APPLE 237 



It is a contagious disease of bacterial origin. The fire 

 blight is caused by very small organisms called bacteria. 

 They are rod-shaped and motile. They multiply by simply 

 dividing and they increase very rapidly. Immense num- 

 bers of bacteria are produced in a remarkably short time 

 and they soon completely fill the infected parts. The bac- 

 teria live almost entirely in the sappy portion of the bark. 



The blight does not attack the fruit, but confines its 

 ravages to the limbs and the trunk of the tree. The disease 

 is first visible on the tips of the younger twigs, which become 

 dried up and later turn black. It spreads rapidly and 

 often wipes out entire orchards in a short time, when it is 

 not fought vigorously. 



The disease is called fire blight because of the character- 

 istic appearance of the foliage. It is also known as twig blight 

 because it is usually first detected on the younger twigs. 

 The disease gains entrance in various ways, as for example, 

 through • wounds left from pruning, and through insects 

 visiting blooms during pollination. However, any abra- 

 sion or wound on the bark of a tree gives a point of vantage 

 for the entrance of the bacteria. There is only one known 

 method of control for this trouble, and that is to cut out 

 all cankers on the limbs and destroy them by burning. All 

 infested twigs should be cut off and destroyed as soon as they 

 appear. When the infected wood is removed see that the 

 pruning tools are thoroughly sterilized by dipping them in 

 a solution of corrosive sublimate after each cut. Spraying 

 is of no avail in controlling the fire blight. 



INSECTS OF THE APPLE. 



Codling Moth. — ^The larvae of this insect cause wormy 

 apples and it is one of the worst foes of the plant. The 

 adult is a small, pale gray moth with brownish spots near 

 the end of the forewings. Surrounding these spots on the 

 wings is an irregular, golden band. The larva of the moth 

 is the common apple worm, which is found feeding in the 

 core of the apple. It is pinkish in color and lives in the 

 apple about twenty days, eating the fruit and growing to a 



