468 



ENCYCLOPEDIA OF PRACTICAL HORTICULTURE 



concentric arrangement. Proceeding from 

 the innermost cavities toward the edge 

 of the spot the cavities become smaller, 

 none at all being found near the edge of 

 the diseased tissue. 



Upon sectioning through a diseased 

 spot the flesh of the fruit is seen to be 

 rotten, brownish and soft, not black or 

 dry, as is the case with the volutella rot. 



Microscopic examination shows the dis- 

 eased tissue to be thoroughly invaded 

 with a thin branching mycelium. 



When this disease is upon twigs, the 

 terminal portions of recent growth die, 

 the bark shrinks and shrivels, turns black 

 and at the line of demarkation between 

 diseased and healthy tissue cracks. The 

 general appearance of such a twig is 

 much like that caused by the fire blight, 

 but is readily distinguished by the pres- 

 ence of very numerous, minute, pimple- 

 like pustules, fruiting cavities distri- 

 buted over the dead part. 



The significance of this fungus upon 

 twigs is twofold: (1) As a cause of the 

 twig blight; (2) as a source of infective 

 material, spores, to transmit the rot to 

 the fruit. 



Treatment 



Spraying coupled with careful pruning 

 out and burning of diseased twigs and 

 branches will doubtless serve as a means 

 of control of this rot, both of branches 

 and fruit. 



F. L. Stevens, 

 West RaleiRh, N. C. 



Fruit Spot 



Phoma pomi Passer 

 This disease is of very common occur- 

 rence in New Hampshire and is found as 

 far south as Maryland and Virginia and 

 as far west as Michigan. It is not so 

 destructive as the scab, but often causes 

 otherwise perfect fruit to go as seconds. 

 It is found on almost every variety of 

 apple, but Baldwins and Tolman Sweets 

 are especially susceptible. The disease 

 appears about the middle of August. At 

 this time it may be seen as spots of a 

 deeper red on the colored surface of the 

 apple and of a darker green on the lighter 

 portion. As the season advances, the 



spots become more prominent. They be- 

 come slightly sunken and more highly 

 colored. Numerous black specks appear, 

 sometimes causing the center of the spot 

 to have an almost uniformly black ap- 

 pearance. The tissue beneath the spot 

 is rendered brown and corky to a depth 

 of several cells. Cold storage seems to 

 check the development of the spots, but 

 in cellar storage they often become more 



Fig. 1. Fruit Spot. 

 (New Hampslaire Experiment Station). 



sunken and spread deeper into the tissue 

 of the apple. They become brown and are 

 much enlarged, sometimes attaining a 

 diameter of one-half inch. 



Recent experiments* have shown that 

 the fungus causing the fruit spot of 

 apples is also responsible for a similar 

 spot on quinces known as "quince 

 blotch." The disease may spread from 

 one host to the other. 



Treatment 



The fungus does not attack the apples 

 until they are nearly grown. Conse- 

 quently, sprayings made in late June or 

 early July are usually as effective if not 

 more so than those made earlier in the 

 year. However, orchards that have re- 

 ceived three and four sprayings for scab 

 will not usually require later spraying 

 for fruit spot. Both Bordeaux and lime- 

 sulphur have given satisfactory results. 

 Charles Brooks 



• Brooks. Cliarles. and Blacli. Caroline A. 

 Apple Fruit Spot and Quince Blotch. Phyto- 



pathoioKv II. o:!-T:i. \;n-2. 



