90 
This coincidence is suggestive, to say the least, and I am inclined to 
believe that the sudden drop in the temperature had something to do 
with this sudden and very unusual prevalence of the curl. Probably 
some other unknown factor also favored the development of the fungus 
in this particular orchard, e. g., some soil condition. This is the more 
likely because no other orchard under observation was anywhere near 
so badly attacked. 
PEACH MILDEW.* 
This mildew has been found occasionally since 1887, but never upon 
many trees in any one orchard. It usually attacks the leaves and 
young stems. On the latter it forms a dense, felt-like, persistent hyphm- 
complex which is first white and afterwards a dirty gray, the epider¬ 
mis being cracked open and destroyed or much injured and a thick 
brown layer of cork being formed under the mycelial patches. The 
mildew produces conidia in abundance, but perithecia have not been 
found, although the search has been continued into winter. 
In Maryland and Delaware particular trees are attacked year after 
year and become stunted, while surrounding ones escape. Often only 
one or two trees in an orchard will be attacked. This fact has been so 
noticeable during the last five seasons that it seemed probable the dis¬ 
ease was brought from the nursery. Its persistence on certain trees 
and the freedom of others was only explainable on the hypothesis of 
some individual peculiarity which I w r as unable to discover. 
This year the mildew was observed in Maryland, Michigan, and 
Georgia, and in central Michigan it was more than usually prevalent. 
At Hubbardston it attacked a dozen very thrifty seedlings in the fifth 
year of growth and apparently for the first time, defoliating the tops of 
the trees in June and July and causing a new growth of leaves and 
branches not unlike incipient hexenbesen. In this case the origin of the 
mildew is unknown, but in case of a Maryland tree known (!) to have 
mildewed in 1889 and 1890, the fungus was found on the unfolding shoots 
so early in the spring and to such an extent as to make it almost certain 
to have wintered over in the form of perennial mycelium. Several hun¬ 
dred leaves and stems were covered with white mycelia and conidial 
fruits prior to the time of blossoming, and in some cases almost before 
the buds were open. No perithecia could be found on this tree and no 
mildew this year or last year on any of the neighboring trees. From 
other trees fresh looking mycelium has been taken in midwinter, and I 
have no doubt as to its perennial nature. 
Later in the season Mr. J. W. Kerr, of Denton, Md., called my atten¬ 
tion to four yearling peach trees which were badly mildewed, although 
they had been grown from fruits procured by cross fertilization and did 
not have the same parentage. The most conspicuous point of agree¬ 
ment was the absence of glands at the base of the leaf blade. Mr. 
* Sphwrotheoa pannosa (Wallr.) Lev. ( ?). 
