EXPERIMENT STATION BULLETINS. 



155 



SECTION IlI.-PLUMS. 



the tendency of the tree to the premature rotting of the fruit or loss of foliage. 



ABBREVIATIONS FOE THIS SECTION. 



Color. 



b. blue. br. brownish. p. purple. 



c. copper. y. yellow. 



r. red. 

 g. green. 



effect on the foliage and also on the curcnlio. The trees should not be 

 sprayed while in blossom, as the bees would be destroyed. The curculio 

 can often be found in considerable numbers on the trees for a week before 

 they bloom. By spraying at that time, many of them would be killed; a 

 second application should be made as soon as the fruit has set, and a third 

 in ten days more. 



BLACK KNOT. 



In many portions of the state the "Black Knot" has appeared on the 

 plum. This is a fungus which causes black wartlike swellings on the trunk 

 and branches of plum and cherry trees; it is also found on wild cherry 

 trees, and in particular attacks the choke cherry. It has destroyed entire 

 orchards in New York and New England, and has practically put an end 

 to plum raising in those localities. Its appearance is a menace to the 

 plum orchards of the state, and active steps should be taken to stamp it 

 out. 



The "knots" should be cut off and hurned whenever seen. The mere 

 cutting off of the infected branch will not prevent the spores from ripen- 

 ing and developing in other trees. By burning the knots the spores will be 

 destroyed. In cutting an old knot from a branch, the cut should be made 

 several inches below the swelling, as the threads of the fungus may have 

 passed dotvn a foot or more below any external signs. 



