198 MASS. EXPERIMENT STATION BULLETIN 170. 



Slime-Flux. 



This trouble is common to trees like the elm, maple, j^ellow birch and 

 apple. It is associated with frost cracks, injury from lightning, splitting 

 of the trunk, defective pruning, etc., and is not uncommonly found in 

 cement-filled cavities. Slime-flux is characterized by the exudation of a 

 slimy, discolored sap from wounds. This exudation of sap is contaminated 

 with various forms of algse, bacteria and fungi, and occasionally with low 

 forms of animal life, all of which give the sap a sour odor. This fermenting 

 mass is apparently poisonous to vegetation, since it will kill the grass 

 upon which it falls, and also causes injury to the bark and underlying 

 tissues of trees. The whitish appearance given to the bark by the slimy 

 sap often persists for some time after the flow has stopped. 



Bleeding wounds often prove injurious to trees, and are very difficult 

 to treat. The bleeding can usually be stopped when it follows defective 

 pruning, as it often does in the elm. Sometimes wooden plugs nicely 

 fitted and driven into the wound firmly will prevent bleeding, and in some 

 cases the tissue may be cauterized by heat. Cement should not be used 

 in cavities that show a tendency to bleed. 



Treatment of Fungous Diseases of Trees. 



The methods of treating fungous diseases are numerous, but undoubtedly 

 in the future different, as well as simpler, cheaper and more efficient, 

 methods will be used. The use of antiseptics in the treatment of wounds 

 and cavities caused by the worst enemy of trees, — i.e., the wood- 

 destroying fungi — is absolutely essential in controlling this type of 

 diseases. 



Little attention has been given to the treatment of the many leaf spot 

 diseases of trees and shrubs, but from what has been already accomplished 

 along these lines we are justified in assuming that these spots can be 

 controlled largely by spraying; for example, trees like the linden, which 

 often becomes badly infected with a leaf spot, are much benefited by 

 spraying. A linden tree,^ sprayed twice during July and August with 

 Bordeaux mixture, retained its leaves ten days later than trees unsprayed, 

 and the amount of leaf spot was materially less on the sprayed tree. 

 (See Fig. 68.) The leaf spot Entomosporium affecting the English haw- 

 thorne may be controlled, according to our observation, by spraying 

 with Bordeaux mixture; and there are many other shade-tree leaf spots 

 that jdeld to this treatment. In many cases, however, it is a question 

 whether the trees are worth the expense and trouble of treatment. 



All the rusts are difficult to control, and it is doubtful whether some of 

 them at least are worth treatment. The rust affecting the Italian poplars 

 (Melampsora) , which at times has been more or less serious, was held 

 in control quite effectively by Prof. S. T. Maynard,^ who sprayed for 



1 Mass; (Hatch) Agr. Exp. Sta. Kept. 15, 1905. 



2 Mass. (Hatch) Agr. Exp. Sta. Bui. 25, 1894. 



