436 Brooks: The Fruit Spot of apples 



Dover, and Nashua. It has been obtained from the following va- 

 rieties : Baldwin, Greening, Northern Spy, Talman Sweet, Red 

 Canada, Canada Baldwin, Red Astrachan, Fall Pippin, Bellflower, 

 Gravenstein, Grimes Golden, Russet, Porter, Snow, Wealthy, Ben 

 Davis, and Mann, besides a half dozen different sorts of native fruit 

 The spots on most of the above varieties are similar to those already 

 described. On the native varieties and on the Talman Sweets 

 the green spots are more common and such brown spots as occur 

 usually have a bright red margin. The appearance on the Tal- 

 man Sweets is quite similar to that described by Clinton (15) 

 under the name of Fruit Speck. On Snow apples the spots are a 

 deep black and have very definite margins. 



Laboratory inoculations 



During the winter and spring of 1 906-07 numerous inocula- 

 tion experiments were made. The apples used in these experi- 

 ments were first washed either in alcohol or in a five per cent. 

 solution of formalin. Spores from pure cultures of the fungus 

 were introduced beneath the epidermis by means of a sterile plati- 

 num needle. From four to twelve inoculations and an equal num- 

 ber of check punctures were made on each apple. These inoculated 

 apples were placed in moist chambers to await developments, 

 than a hundred apples have been treated in this manner, 

 of these were Baldwins, but Yellow Transparents, Manns, Astra- 

 chans, Red Canadas, Greenings, and Porters were also used. Bald- 

 wins removed from the culture chambers after two weeks time 

 usually showed little or no contrast between the inoculations an 

 punctures. The same condition was sometimes found at the en 



More 

 Most 



of three weeks. After four weeks time there was always a 



marked 



brovn 



contrast (plate 31, figure 2). In the punctures the nee 

 path looked practically as clear-cut and fresh as when first ma t 

 The inoculations showed on the surface of the apple as 

 sunken spots. A study of the underlying tissue showed that o* 

 cells around the needle path had shrunken and collapsed making 

 a much larger opening than the original one. The tissue ** 

 browned for a radial distance of one to three millimeters (plate 3^ 

 figure 4). When vascular bundles were near the needle path t J 

 browning extended several millimeters farther along their cour 



