DISEASES OF PLANTS. 1051 



Notes on Gymnosporangium macropus, F. I). IIeali) (A ()■■<. in Srirncr, n. 

 scr., 27 (I'JOS), N0.6S-',, pp. 210, ;.^//).— Invcstijintioiis riirriod on by the author 

 with G. nidcropiiN have shown that 2 years are required before the cedar apples 

 reach maturity. Younj; cedar apples can be found nearly a month before the 

 rust spots on the apple leaves have matured any a'cidiosi)ores. I^urlns the 

 past season a'cidiosi)ores were found in viable condition from July to October 

 22, but these spores produced no evident infection until the spriufj of the next 

 year, when growth was resumed and the younj: cedar apples became visible. 



Apple leaf spot caused by Sphaeropsis malorum, W. M. Scott and J. B. 

 ItoKiiii {U. S. Dcpt. A<n:, Bur. I'luiit Indus. Bui. 121, pp. //7-.>//, pis. ,?).— The 

 leaf si)ot of apitles has been attributed to a number of different fungi by difler- 

 ent investigators, and in connection with a study of some of the diseases of 

 the apple the authors have examined the subject and found that, contrary to 

 the general belief, the leaf spot is caused by aS'. malorum. 



In their investigations the authors found that a number of fungi were present 

 in the spots, and cultural studies as well as inoculation experiments gave evi- 

 dence that the black rot fungus of the fruit also attacks the leaves, causing 

 the circular or irregular spots characterizing the leaf spot disease. In addi- 

 tion to tS'. malorum. Coniotlnjrluni pirina occurs abundantly on the ai)i)le leaf 

 spots, and species of Hendersoiiia, Coryueum, I'estalozzia, and Alternaria were 

 observed, but are believed to be saprophytic. 



In si»raying experiments for the protection of apples from fungus attacks, it 

 was found that the leaf spot was prevented whenever the trees had been thor- 

 oughly sprayed with Bordeaux mixture. Where it is desired to control the leaf 

 spot alone, without reference to diseases of the fruit, 2 or 3 applications of weak 

 Bordeaux mixture during the season will be found sutticient. 



Some apple leaf spot fungi, C. P. Hartley (Ab.s-. //( Science, n. scr., 27 

 (IDOS), No. GS.'i, p. 212).— The author reports having found in West Virginia 

 IS species of fungi that produce leaf spots on apples. The commonest of these 

 are Coniothijrium pirina, Conjncum foliicolum, Spha'ropsis malorum, and an 

 undetermined species. 



A stem disease of the cocoanut palm, T. Fetch (Circs, and Agr. Jour. Roij. 

 Bat. Gard. Ceylon, 4 (1907), No. 8, pp. 49-53, pi. 1). — A disease of cocoanut 

 l)alms which has been under observation for sometime is described. It is char- 

 acterized by the exudation of a brown liquid through small ci'acks in the stem, 

 the liquid forming on the surface rusty patches, which afterwards turn black. 

 On cutting the stems through these places, the internal tissues are generally 

 found decayed, and iuunedintely beneath the cracks the tissues are black and 

 surrounded by a wet brown zone, in which tlie rot appears to be advancing. 



The progress of the disease seems to depend upon the age of the trees. On 

 young trees the injury spreads rapidly and the trees die in 5 to G years, while 

 old trees having dense woody tissues seem to be resistant. The disease does 

 not, so far as present observations go, seem to be able to desti-oy old trees. 



Various opinions have been advanced regarding the cause of this disease, but 

 the author reports having observed at the advancing stage of the disease the 

 fungus Thielaviopsis ethaceticus. This fungus causes the pineapple disease of 

 sugar cane as well as a destructive disease of pineapples. In addition to this 

 fungus, diseased tissues have shown another. Porta ravcnchr, but this is be- 

 lieved to be a saprophyte. 



On account of the rapid and destructive spread of this disease among new 

 plantations, the author recommends the cutting out and burning of the diseased 

 tissues as soon as noticed. 



The immunity of the Japanese chestnut to the bark disease, H. Metcalf 

 {U. /S'. Dept. Ayr., Bur. Plant Indus. Bui. 121, pp. 55, 56). — Attention is called 



