Oct. 13 /1933 
A New Tumor of the Apricot 
59 
(2) The most characteristic feature of the histology of this disease, 
apart from the phenomena of gummosis and hyperplasia, is the diver¬ 
gence of cork strands from their normal course on the exterior of the 
phloem to penetrate the phloem tissue to relatively great distances, 
reaching sometimes close to the cambium. 
(3) The etiology of the disease has not been established with absolute 
certainty. A fungus, a species of the genus Monochaetia Sacc., was 
isolated in pure culture from the interior of the galls. When inoculated 
into the limbs of a healthy old apricot tree, galls were produced which 
were identical in their gross anatomy with the natural galls. From 
these the fungus was readily reisolated in pure culture, and reinoculation 
experiments started. Unfortunately, the trees on which these were 
made were pulled up before the galls had time to form. The tree on 
which the original inoculations were made was also pulled up before the 
resulting galls had become very large. A microscopic search for organ¬ 
isms in the tissues of the galls failed to reveal the presence of either 
fungous mycelium or bacteria. 
(4) No young trees were found affected in nature. Inoculations into 
young trees resulted in gumming cankers which after several months 
became stationary, but no galls were formed. 
(5) Control measures based on excision and the application of Bor¬ 
deaux paste gave fully satisfactory results. 
(6) The results of a search of the available literature, both with 
regard to the diseases described on the apricot and to those attributed 
to members of the genus Monochaetia and its close ally Pestalozzia, seem 
to justify the belief that this disease has never been described before. 
(7) Similarly, Monochaetia rosenwaldia , which is believed to be the 
causal agent of the disease, seems different morphologically from the 
known species of the genus whose descriptions are available. In view 
of this fact and particularly in view of the parasitism of this organism, 
the like of which is unknown among members of the genus Monochaetia, 
it is regarded as a new species. 
literature CITED 
(1) Durand, Elias J. 
1911. This differential staining of intercellular mycelium. In Phyto¬ 
pathology, v. 1, p. 129-130. 
(2) Fischer, Cecil E. C. 
1909. NOTE ON THE BIOLOGY OF PESTALOZZIA HARTlGH, TUBEUF. In Jour. EcOIl. 
Biol., v. 4. p. 72-77, pi. 7. 
(3) Hennings, P. 
1896. ueber Eine auffallige gallenkrankheit nordamerikanischer 
ABIES-ARTEN IN BERLINER BOTANISCHEN GARTEN, VERURSACHT DURCH 
pestalozzia tumefaciens p. henn. n. sp. In Verhandl. Bot. Ver. 
Brandenb., Jahrg. 37 (1895), p. xxvi-xxviii. 
(4) LEE, Arthur Bolles. 
1913. the microtomist’s vade-mecum. Ed. 7. x, 526 p. Philadelphia. 
(5) Lindau, G. 
1900. MEL anconialES. In Engler, A., and Prantl, K. Die natiirlichen 
pflanzenfamilien, Teil i, Abt. i,** p. 398-415, fig. 206-216. Leipzig. 
(6) Meinecke, E. P. 
1915. spore measurements. In Science, n. s., v. 42, p. 430-431. 
(7) Saccardo, P. A. 
1906. sylloge fungorum. v. 18. Patavii. 
(8) SolEREdER, Hans. 
1908. systematic anatomy of the dicotyledons. Transl. by L. A. Boodle 
and F. E. Fritsch. Rev. by D. H. Scott, v. 1, xii, 644 p., 153 fig. 
Oxford. 
