Fig. 14. Normal plasftiodinm as found in early stages of the disease, X 600. 
15. Aggregated appearance of plasmodium x 300. 
16. Section showing another aggregated appearance in which Ihe spherical 
masses are much smaller, X 200. 
FIELD NOTES, 1891 . 
By Erwin F. Smith. 
It can scarcely be doubted tliat climatic conditions exert a marked 
influence on tlie spread of many fungous diseases. Bad weather may 
render the host more susceptible, or only afford the parasite increased 
facilities for multiplication, or both. Under just what set of conditions 
in particular cases the fungus is most likely to attack the host, or is 
certain to do so, are points on which, for the most part, there is not 
yet enough evidence to decide positively, but as time goes 011 we may 
confidently expect to see many of these problems worked out fully, 
our knowledge of the complex relations of host and parasite being yet 
only in its infancy. 
In this series of notes my desire is simply to put on record certain 
observations which may contribute toward the solution of a most inter¬ 
esting problem of phytopathology. There is no doubt that mycolo¬ 
gists must become closer observers of local weather conditions and of the 
individual, varietal, and specific peculiarities of plants, if they would 
satisfactorily explain the behavior of many fungous diseases. 
PEACH CURL* 
It is well known that gardeners and fruit-growers have frequently 
ascribed this disease (mildews, also) to the depressing influence of cold. 
Mycologists, on the other hand, since the discovery of Taplirina, have, 
perhaps too generally, assumed the direct cause to be the only neces¬ 
sary factor in the production of curl. 
The conditions under which peach curl appeared in the orchard 
of Mrs. W. O. Shallcross, at Locust Grove, Md., in the spring of 1891, 
are so peculiar and bear so directly on the point at issue that it seems 
worth while to set them down somewhat fully. This orchard contains 
about 1,050 trees, now set five years. It is situated on the east side of 
Chesapeake Bay, on loose, thin upland, in a region of extensive orchards, 
the nearest being about one-half mile distant. Peach curl due to Taph- 
rina is not troublesome in eastern Maryland or Delaware. It was present 
in quantity for the first time in many orchards in Kent County, in 
1890, and was so much more than usually abundant everywhere as to 
receive notice in this Journal (Vol. vi, p. 107). Probably there was 
more or less of it in this orchard, but not enough to attract special at¬ 
tention. 
* Taphrina deformans (Berk.), Tul. 
