Blackspot Canker. 95 



When it is understood that the eight boxes used in this experiment 

 were selected and handled with more than ordinary care and that at the 

 time they were examined were perfect except the areas where the 

 fungus had gained an entrance, it is easily seen that greater care must 

 be taken in preventing the spread of the disease. Data is not available 

 which shows the relative abundance of the spots upon the apples given 

 in the above statement. During the Winter of 1910 the writer, however, 

 had an opportunity to observe the apple rot developed on a quantity 

 of Rhode Island Greening, which had been stored in boxes in a cellar. 

 Of this lot of fruit 197 apples were inspected on January 30, 1911. There 

 were a total of 1,023 decayed areas, 221 of which were larger than one- 

 half inch in diameter, 139 areas were producing spores, 24 of which were 

 slimy, the remainder being either or only slightly waxy. The fungus 

 had entered through 68 scabby areas, eight injuries done by the bud 

 moth, 15 mechanical injuries, four through the blossom end and five 

 through the stem end, the remainder passing through the uninjured 

 epidermis. 



In the examination of this fruit which had been stored in two boxes, 

 it was observed that apples with large discolored spots on them were 

 distributed throughout the boxes, indicating that the spores had lodged 

 upon the apples before the same were gathered. It was also noticeable 

 that the apples in the bottom of the boxes were literally covered with 

 decaying spots. In one case one group of 30 apples had eight large 

 spots and 406 smaller ones. The observations made confirm previous 

 observations indicating that as the spores mature the gelatinous sub- 

 stance surrounding the spores absorbs a large quantity of water from the 

 atmosphere, finally going into Solution. These masses of liquid con- 

 taining spores finally run off, falling on the fruit beneath. Many times 

 these drops splash from one apple to another. A line of small areas 

 down the side or a group of spots show how the liquid splashed, scatter- 

 ing the spores. 



The recognition and control of the diseases caused by fungus which 

 is now known under the scientific name of neofabrea malicorticis (Cord- 

 ley) Jackson is of great importance to all the growers of the apple, since 

 the disease of the body of the tree directly threatens the life of the 

 plant and serious losses of apples held in storage will occur in cases 

 where the spores of the fungus lodge on the fruit before the apples 

 are gathered. It is apparently true that spores lodge on the fruit 

 some days before the general harvest of the apple crop takes place, 

 since the early maturing apples are as subject to the rot as the later 

 maturing varieties that may hang on the trees until the advent of the 

 early autumn rains and later. 



The discovery that there are two spore forms developed in each 

 canker, and that the conidial matures the first year and the ascigarous 

 the second year, should make the orchardist doubly cautious in attempt- 

 ing to eradicate the trouble, since the distribution of spore forms con- 

 tinues through so long a period and that damage to the body of the tree 

 as well as the loss of the fruit after the crop has been placed in storage 

 is apt to occur. 



Owing to the fact that tests with lime-sulphur and Bordeaux mix- 

 ture made on mature fruit shortly before picking time has at least given 

 good indications that the fruit may be sprayed without injury, it seems 

 advisable to resort to spraying in order to prevent loss of fruit in storage, 

 especially in all cases where fruit is taken from diseased trees. Past 

 seasons' experiences also indicate that such an application would no 

 doubt be of great value in preventing the spread of late infection 

 of apple scab which frequently takes place after the fruit has been 

 wrapped in paper and placed in storage. 



