NEw YorK AGRICULTURAL EXPERIMENT STATION. 313 
Headden says,* “There is no resemblance between our cor- 
roded crowns and the King disease, known as Collar rot,” they 
are probably the same disease. 
CRITICAL SUMMARY OF THE PRIMARY CAUSES OF 
CROWN-ROT. 
There are, then, three distinctly different primary causes 
put forth by these various observers in accounting for Crown- 
rot — parasitic organisms, arsenical poisoning and low tem- 
peratures. 
PARASITIC ORGANISMS. 
Those holding to the idea that parasitic organisms are pri- 
marily responsible for this trouble base their conclusions 
largely upon circumstantial evidence. Nothing in the publica- 
tions by Cavara, Aderhold or Wilcox, referred to above, can 
be considered proof that the fungi discussed are other than 
Saprophytes, or at most wound parasites. Neither Cavara nor 
Wilcox records inoculation experiments. It seems probable 
that Wilcox’s “root-rot” is Crown-rot with the presence of 
his Clitocybe parasitica. Aderhold tried some infection ex- 
periments, but from them it is more logical to conclude that 
the fungus was very remotely, if at all, connected with the 
production of discoloration in the roots of his nursery trees. 
Although von Schrenk appears to have gotten some positive 
results with Thelephora galactina as a parasite of apple-tree 
roots, the indicated distribution and characteristics of the 
disease make it possible to assume that 7’. galactina is per- 
haps a wound parasite gaining entrance to the wood through 
frost or other injuries. The suggestion by Whetzel, that the 
“ fire-blight ” Bacillus may cause the King disease or Crown- 
rot, probably belongs in the same category. 
ARSENICAL POISONING. 
It stands to reason that, when arsenical sprays are applied 
to fruit trees for years, arsenic will accumulate in the soil 
*In a reply to Ball on “ Arsenical poisoning of fruit trees,” in the 
Journal of Economic Entomology, 2: 243. 1908, 
