SYMPTOMS OF DISEASE (SYMPTOMATOLOGY) 



345 



2. Shot-holes (Fig. 135). — The perforations of leaves and the forma- 

 tion of what are called shot-holes illustrate another form of fungous 

 attack, where circular patches of dead tissue killed by the fungus drop 

 out leaving a hole. The English morello cherry trees in some sections 

 of our country have been killed during the past_few years by this " shot- 



FlG. 13s. — Shot-hole disease of the plum due to Cylindrosporium padi. (After 

 Heald, F. D.. Bull. 135 (Sci. Ser. 14). Univ. of Tex.. Nov. 15, 1909.) 



hole" disease. When the funguses belonging to the genera Cercospora 

 and PhyllosHcta attack the leaves of Virginia creeper perforations may 



be formed. 



3. Wilting. — Wilting in general is due to the lack of sufi&cient water 

 to supply that lost by transpiration, for wherever the amount of water 



