384 OHIO EXPERIMENT STATION: BULLETIN 214 
Root-Rot. Since the recent demand for seedling trees of Catalpa speciosa, 
some difficulties have been met with in diseased seedlings of catalpa. These 
seedlings are liable to be attacked in their early stages by the ordinary damp- 
ing off fungi such as Rhizoctonia, Pythium and Botrytis. One interesting case 
of a true root-rot fungus was studied in 1908. The seedlings were being grown 
in land that has been used some years for truck gardening; the stand was cut 
down very much and in later summer some of the seedlings, then afoot or more 
in height, showed sudden dying and dropping of the leaves; this was found to be. 
due to the root-rot fungus of the violet and tobacco (7hielavia basicola Zopf.). 
This must have been quite serigus on the smaller seedlings. At the date of 
study, September, only the smaller root branches were destroyed by it and the 
larger ones seemed normal. The injury to these seedlings in dry weather was 
enough to bring about leaf collapse due to reduced water supply. If this fungus 
becomes very general it will involve soil treatment for such seed beds. It was 
too soon to determine how serious it may be upon trees of larger nursery size, 
although it is not greatly feared. 
; CELERY 
Black-Root, so-called, may be found on celery plants from seed beds. In one 
instance such plants yielded growths which shortly run to seed and were 
valueless. 
a] 
Fig. 38. Celery leaf attacked by leaf-spot. Various troubles produce similar 
spotting in celery leaves. 
Leaf-Spot or Leaf Blight (Cercospora Apiti Fres.) is a prevalent condition 
upon celery plants. This is at times attributed to the fungus above named, or 
others, and is also produced by other causes, as by excess of water devine 
overflow and the like. During certain seasons the loss from thé leaf-spot or 
leaf-blight troubles is very much greater than during others. 
i This.is clearl 
explained when the conditions giving rise to the a : 
