354 MAINE AGRICULTURAL EXPERIMENT STATION. IQIO. 



ter especially on fruit left on the trees or on the ground it is 

 probable that much of the spring infection conies from tlie win- 

 ter spores formed on the fallen leaves. It is a matter of common 

 experience that the lower leaves on the tree are the first to show 

 attacks of scab in the spring. Hence raking and burning the 

 leaves would do much to lessen the danger of infection. The 

 formation of winter spores takes place more readily when the 

 leaves fall on sod or are partly covered by grass, other leaves, 

 etc. Orchard cultivation produces conditions unfavorable to 

 the propagation of scab spores and early spring plowing buries 

 many of them where they will decay and do no damage. 



Scab on the fruit is too familiar to need much description. It 

 first appears as small, circular, olive-colored spots on the skin 

 of the apple, these later enlarge, many of them becoming one- 

 fourth of an inch or more in diameter, roundish, rougliish and 

 dark olive-colored, usually surrounded by a light gray border. 

 Several spots may coalesce and form irregular patches, some- 

 times covering a large portion of the apple. In severe attacks, 

 especially those resulting from early infections when the fruit 

 is small, the apples often become cracked and badly distorted 

 in shape due to the unequal growth of the healthy and diseased 

 portions. Fig. 245 represents an apple in this condition. 



While scab on the fruit is largely a superficial growth, the in- 

 jury it does directly and indirectly is by no means confined to 

 simple damaging of the appearance of the fruit. As is pointed 

 out elsewhere in this publication (p. 364) epidemics of pink rot 

 and some of the blue mold decay come from secondary infections' 

 of these fungi through scab spots. Scabby apples in addition 

 to being more likely to decay wither more rapidly in storage than 

 do perfect apples. 



In a former publication of this Station attention was called 

 to what then appeared to be a rather novel and uncommon form 

 of the development of scab on ap])le fruit — its appearance and 

 growth on apples in storage cellars.* Since the publication of 

 this article certain more or less general statements have been 

 found in the early Station literature indicating that somewhat 

 the same thing had been noted and recorded at least 20 years 



* Morse, W. J. Me. Exp. Sta. Bui. 164, p. 4, 1909. 



