336 The Ohio Naturalist. [Vol. XI, No. 6, 



The fungus is also present on the water sprouts (Fig. 4) and 

 fruit spurs where it fomis tan-colored cankers. These cankers on 

 the water sprouts are variable in size, often attaining a length of 

 two inches, and a width of about one-half inch. The cankers on 

 the fruit spurs are smaller, being usually about a quarter of an 

 inch in diaineter. However, the cankers are more numerous than 

 on the water sprouts and often give the fruit spurs a very rough, 

 ragged appearance due to the cracking of the cankered tissue. 

 vSometimes the cracks may entirely separate the infected from 

 healthy tissue, and then the canker wound will be healed by the 

 growth of the new tissue which crowds away the infected bark. 

 The pycnidia are found scattered over the entire canker surface 

 and the spores therein are similar to those found on the fruit. 



The leaves, when infected with Phyllosticta solitaria, show 

 small yellow spots about a sixteenth of an inch in diameter. In 

 the center of these irregular spots there usually can be found one 

 or more pycnidia which contain the spores. The presence of the 

 spots on the leaves are often lacking, especially when the foliage 

 has been protected b\' ijropef spraying. 



From the trees observed in this state, it is evident that very 

 little infection comes from the infected leaves, but the perennial 

 cankers on twigs, with their numerous pycnidia, are the great 

 source of infection. The blotches, which give the apples their 

 unsightly appearance, begin to appear late in July or in the early 

 part of August and increase in size vmtil harvesting (Fig. 2). 

 These apples when kept in storage soon decay, because, through 

 their injured epidermis other fungi enter. 



As to the control of the apple blotch, it is reported by several 

 of the fruit growers that spraying will control this disease. How- 

 ever, it has been observed that the blotch was prevalent to a great 

 degree on certain trees that were well sprayed. The blotched 

 apples in such cases would tend to discredit the nse of sprays were 

 it not for the fact that the trees were usually not well pruned, 

 and hence the cankers were allowed to send forth their spores 

 unhindered. It appears that spray treatment must extend 

 throughout the season after the manner of sprays for bitter-rot. 

 Thus it is clearly seen that while spraying is a great factor in the 

 control of the apple blotch, ])runing plays just as important a 

 role in checking a disease which is costing many bushels of apples, 

 and which, if not checked, will ruin some of the choice crops in 

 this state. 



Date of Publication, April ,5, 1911. 



