CITIZENS OF THE APPLE-TREE 95 



bodies or winter-spores mature. A rain discharges them 

 in astonishing numbers. Rising in the air (for they are 

 incredibly light), these spores lodge on the unfolding 

 leaves and flowers of the apple, and there begin to ger- 

 minate, invading the tissue". The tissue is penetrated 

 and killed so rapidly that the practiced eye soon discovers 

 a "spot." The leaf, if badly infected, may not reach 

 full size ; it may curl ; it may die and fall ; the tree thereby 

 is injured. 



From the fungus in the active diseased areas, an- 

 other kind of spore develops rapidly. It is the summer- 

 spore, which may be produced in prodigious numbers, 

 and being discharged carries the disease elsewhere. 



All summer the process of spore-formation and dis- 

 tribution keeps up. If conditions are favorable, the tree 

 is invaded in foliage and fruit. The flower-stems in the 

 unfolding buds are attacked by the winter-spores and the 

 flower falls. The apples become spotted from the in- 

 vasion of the summer-spores, perhaps misshapen. Late 

 infections may not show at picking time, but develop on 

 the fruit in storage. The affected leaves are cast in the 

 autumn, the winter-spores begin to form, the snows come 

 and hide the processes, in spring the spores mature ; and 

 so does the round of life go on and on. 



There are beautiful forms in these fragile fungus 

 threads that eat their way into the tissues of the host. 

 There are fascinating phenomena in the growth and re- 

 production. Even so and for all that, man protects his 

 tree by spraying it with poison, and thereby again does 

 he have dominion. 



The spraying for apple-scab is with lime-sulfur to 

 which may be added arsenate of lead. This treatment. 



