SPECIAL REPORT FOR YEAR I912, 39 



Three very common diseases of the stone fruits as usual did 

 much damage within the State last season, and many specimens 

 of them were received. These are the brown rot, black knot 

 and plum pockets. 



More specimens of brown rot of the plum were received last 

 season than for several years. The disease also attacks the 

 cherry and the apple in this State, and is one of the most 

 destructive diseases of the peach farther South. Last season 

 it was reported from Bar Harbor as doing considerable damage 

 where the English custom of growing peaches under glass is 

 carried on commercially. In 191 1 a very severe outbreak of 

 brown rot was reported from a cherr}^ orchard where not only 

 were the young fruits destroyed but young branches and twigs 

 were killed back by the fungus. Plum fruits are attacked by 

 brown rot about the beginning of the ripening period. The 

 diseased portions turn brownish, forming soft spots which 

 rapidly grow in size till the whole fruit is infested. The fungus 

 then breaks through the surface in the form of small grayish 

 tufts or nodules which are masses of summer spores which 

 scatter and infect healthy fruits. The decayed fruits dry up 

 and form mummies which hang on the trees, or fall to the 

 ground. In either case these mummies are the most important 

 means of carrying the disease over winter and serve as the 

 source of the new infections of the following seasons, when the 

 young twigs, flowers and young fruit may be attacked. 



The mummied fruits should be destroyed in the fall, and the 

 trees sprayed wath a 5-5-50 bordeaux mixture early in the 

 spring before the leaves appear. After the leaves appear the 

 trees should be sprayed with lime-sulphur the same as is used 

 on apple trees. See Bulletin 185 mentioned above. 



Black knot is too common to need description. It is especially 

 common in Maine on wild cherries, particularly the chokecherry, 

 which is one of the sources of the spread of the disease to 

 cultivated plums and cherries and these plants should be rooted 

 out and destroyed wherever found. The knots on the culti- 

 vated cherries and plums should be pruned out and burned as 

 fast as they appear. The trees should be sprayed in the same 

 way as described for brown rot. 



Plum pockets, judging from observation and from the num- 

 ber of specimens sent in, appears to be a widely distributed and 



