56 
Journal of Agricultural Research 
Vol. XXVI, No. 2 
naturally in the bark and which expose the deeper layers of the phloem 
to infection, gives a plausible explanation of the susceptibility of the 
Moorpark variety, and the occurrence of the disease exclusively in old 
trees. 
control work 
The treatment which naturally suggested itself in this connection was 
that of removing the galls by excision. Fifty galls of various sizes were 
cut off on May 19, 1916. Among these were very small eruptions just 
making their appearance, as well as older galls up to 8 inches in lengths 
The bark surrounding the visible swellings for a distance of 1 to 2 inches 
was carefully examined. In most cases it was found to contain gum 
pockets and was therefore removed. It was thought necessary to 
remove some of the tissue which showed no visible signs of disease, 
along with the diseased tissue. All wood with fresh gum pockets in it 
was gouged out. Relatively wide areas filled with dry gum were often 
found extending into the wood. While these lesions were not consid¬ 
ered a possible source of reinfection, they were thoroughly gouged out 
as a provision against wood decay. The wounds formed in this manner 
were smeared with Bordeaux paste (bluestone, 1 pound to 1 gallon of 
water; quicklime, 2 pounds to gallon of water). 
None of these galls returned during the years 1916 and 1917. It 
is safe to say, therefore, that the disease can be held in check in the 
manner described in the foregoing paragraph. This can be accomplished 
at a relatively low expense if the galls are removed while small. It is 
hardly necessary to point out in this connection that limbs which have 
been encircled by the gall, or nearly so, are past treatment. A complete 
removal of affected tissue in this case would necessitate the ringing of 
the limb, which would result in its death. 
THE PROBABLE CAUSAL AGENT 
Monochaetia ro senwaldia Khaz, n. sp. 8 
A careful comparison of the characteristics of this species of Mono - 
chaetia with those of all the species of the genus listed by Saccardo (7),. 
as well as with a number of other newly described and yet unlisted species, 
seems to show that the parasite in question is a new species. Not 
only is there no other species of this genus resembling it in its mode 
of parasitism, but none of them is identical with it in morphological 
characters. 
The writer takes occasion, therefore, to name this fungus Monochaetia 
rosenwaldia Khaz. after Julius Rosenwald of Chicago, Ill., to whom he 
8 Monochaetia rosenwaldia belongs to the Imperfect Fungi. The genus is characterized by acervuli and 
conidia which are at least two-septate, the apical and basal cells of which are more or less hyaline. The 
most distinctive feature of this genus, however, which separates it from its ally, the genus Pestalozzia De 
Not, lies in the matter of apical appendages, of which Monochaetia has only one, while the conidia of Pesta¬ 
lozzia have several cilia. It was on the basis of this purely abitrary distinction that Saccardo raised the 
group from a subgenus of Pestalozzia to the generic rank (7, p. 485; 5, p. 411 ). 
The genus Monochaetia is composed largely of saprophytic species. The genus Pestalozzia, on the other 
hand, contains a number of plant parasites, and of these there are two whose mode of parasitism seems to be 
more or less similar to that of Monochaetia rosenwaldia. They are: 
(1) Pestalozzia hartigii, generally considered the cause of a disease affecting a variety of tree and shrub 
seedlings in the nursery which manifests itself in the constriction of the stem just above the soil and results 
in the death of the affected plant. Fischer (2) reports that he failed to obtain infection from inoculation 
with this fungus into an extended range of seedlings. 
(2) Pestalozzia tumefaciens P. Henn., to which Hennings (3) ascribes a disease found by him on severa 
spedes of Abies. This disease manifests itself by the formation of “gall-like swellings” on the branches. 
The internal consistency of these galls is also described, but, unfortunately, in rather indefinite, nontechnical 
terms. Since no anatomical features are mentioned in his description, no conclusion can be drawn with 
regard to the similarity of that disease to the apricot gall. 
