SCALD, OR EDGE BURN. 179 



quarter of an inch. Under exceptional circum- 

 stances nearly the entire leaf may be involved, 

 and there is then left only a small green area in 

 the center. Once the injury is done, there is of 

 course no remedy, and all efforts should be made 

 to keep the plants in such a condition that the 

 trouble cannot be brought on. 



One serious after effect of the difficulty is the 

 liability of the plant to be attacked by a number of 

 species of fungi. Although fungi are not the 

 direct cause of the trouble, there are many species 

 which will attack partly dead tissues and from 

 them extend into the healthy parts of the leaf. 

 It is not uncommon, therefore, to find plants 

 affected with this scald, or edge burn, collapsing 

 from the effects of fungi which have first attacked 

 the diseased portions and through them have 

 gained sufficient strength to destroy the unaffected 

 parts of the leaves. 



A species of Botrytis is very apt to work on 

 such affected parts, especially if the weather is 

 damp and the sun does not shine for several days 

 in succession. The tissues in such cases get soft 

 and slimy and it is very difficult to keep the 

 plants clean. 



The trouble may be brought on by a number 

 of causes. It is often the result of using strong 

 liquid manure, either organic or in the form of 

 chemical fertilizers. Such liquids when applied 

 to the soil and roots seem to temporarily check the 



