New York AGRICULTURAL EXPERIMENT STATION. 107 
trouble in the laboratory by getting into fungus cultures, but 
whether they feed upon the fungi or upon the culture medium is not 
clear. 
Concerning the second hypothesis it is plain that the mites may 
carry the spores from bud to bud and thus spread the disease, but 
in order to account for the constant association of the mite and 
fungus it is necessary to go further and establish a motive for the 
mites visiting the buds. If the mites go to the diseased buds merely 
to feed on the decaying tissue or to breed in it there would be no 
object in visiting healthy buds. Although we have been unable to 
demonstrate it, it seems probable that the mites do visit healthy 
buds, presumably for the purpose of feeding upon the tender tissue 
of the floral organs. This would be quite in harmony with the 
known feeding habits of this species, it having been established by 
Reuter* that it attacks the tender living tissue of grass culms. As 
previously stated, our attempts to produce bud-rot by means of the 
mites alone, have failed. Altogether, 12 buds were inoculated with 
mites, apparently without any injurious effect on the buds. How- 
ever, the negative results in these few experiments have little 
weight. The conditions surrounding the plants may have been un- 
favorable to the mites. 
The fact that the disease sometimes destroys the interior portion 
of the buds before the latter have even begun to open, is strong evi- 
dence that the spores of the fungus are carried into the buds by 
some animal. It seems scarcely possible that the spores could get 
into such tightly closed buds in any other way. In such a situation 
suspicion would-naturally point to thrips, two or three species of 
which frequently attack carnations and often enter the buds. 
However, our studies tend to exonerate thrips of any connection 
with the disease. Mites are the only animals found in the diseased 
buds. 
Some species of Sporotrichum are parasitic on insects, and 
Kirchner*®? has observed a species of Sporotrichum apparently 
parasitic on the mite Tarsonemus spirifex Marchal, but there is no 
reason to suspect that Sporotrichum poe bears such a relation to the 
mite in the carnation buds. 
To sum up: The hypothesis which offers the most rational ex- 
planation for the constant association of the mite and the fungus 
“Reuter, Enzio. (See footnote No. 15.) 
* Kirchner, O. Eine Milbenkrankheit des Hafers. Ztschr. Phanzenkrank 
SA I3rI8: 1904. 
