216 THE APPLE 



winds, but have not the power to reinfect apples. Finding the 

 original host plant, the cedar, the spores lodge there and start a new 

 growth, producing ultimately cedar balls or cedar apples — round, 

 reddish, gall-like swellings, usually less than an inch in diameter. 

 The galls begin their growth on cedar twigs during the early 

 summer months, pass the winter there, and renew growth the 



Fig. 96. Powdery mildew on leaves. (University of Maine) 



following spring. Full growth is reached the second fall after the 

 start of the infection. The second spring, in wet weather, yellow 

 jelly-like growths protrude all over the balls. From this gelatinous 

 mass is produced a second and smaller crop of spores, which, 

 when dry, are like dust and may be carried by winds to apple 

 trees, where they infect the foliage and the fruit, causing the 

 abnormalities described above. 



