DISEASES OF PLANTS. 741 



Qloposporiuni i)iorinu»i, Mdisonin tiu tl'iciurtnix, Onilaria medicaginifi. and Altcr- 

 naria tenuis), root canker (Rliizoctoiiia rioUiccd), club root i Uroithhictis alfal- 

 fa'). Onibauchc nihcia^. and Cnscnta. 



Plant-like Actinomycetes, J. Peklo {CcutbL Bald, [etc.], 2. Abt., 27 (1910), 

 A"o. 17-21. pp. .'i.')l--J7iK Jiyx. 11)3). — The author gives an extended discussion of 

 the taxonomic position of the organisms inhabiting the root tubercles of Alnus 

 (/lufinosa and Mipica gale, in which their morphological characteristics and 

 general nature are compared with those micro-organisms found in other tubercles 

 (root tubercles of legumes, tuberculosis tubercles, etc.). The conclusion is 

 drawn that these tubercle bacteria belong to the genus Actinomyces. 



A serious disease of plants in Para, C. F. Baker (Amer. Rev. Trop. Agr., 1 

 {1910). yo. S-'i. pp. 99-101). — Attention is called to a very serious and widely 

 disseminated disease dne to nematodes ( Heterodera ) , which makes impossible 

 the cultivation of tomatoes, cabbage, radishes, turnips, tobacco, cotton, etc.. on 

 old lands about Para. 



Crop rotation with uoususceptible plants, clean culture, and the removal and 

 burning after each harvest of all remaining roots, are suggested. 



Nematode control by trap plants, A. Postelt {Wiener Lamhc. Ztg., 60 

 {1910). Xo. 9. pp. 79, 80). — In experiments on the control of nematodes infest- 

 ing sugar-beet lands, several crops of rape and turnips were used as trap plants, 

 resulting in a marked decrease in nematode injuries on land thus treatetl. 



On the erg-ot of wild and cultivated grasses, B. Baknas {Math. u. Naturw. 

 Bcr. Uityani, 24 {1906) [pub. 1909], p. 377; ub.s. in Rir. Patol. Veg., 4 {1910), 

 No. 9-10, p. 132). — The sclerotia of ergot {Claviceps purpurea) is reported on 

 Horcleum nudum, Lolium tcmulentum, Triticum caninum. Agropijrum barbu- 

 latum, and Aira flexuosa, which with those heretofore reported make 35 hosts 

 known for this fungus. It is claimed that the infection of cultivated grasses 

 does not occur usually from ascospores. but more probably from conidia found 

 in the so-called honeydew. as the inoculation of T. repens, Daetylis glonierata, 

 and Bromus inrrmis was successful with these spores from cultivatwl plants. 



On the dissemination and appearance of the root fungus of alfalfa (Rhi- 

 zoctonia violacea) in Franconia, G. Laurer {IUus. Laiidic. Ztg., 30 {1910), 

 No. J/S, pp. 439-441, figs. 5). — A general discussion is given of the characteristics 

 and prevalence of this disease, together with the results obtained from experi- 

 ments in combating it in which carbon bisulphid, creosol, liquid manure, quick- 

 lime, and copper sulphate were used. The liquid manure, creosol, and quicklime 

 proved of value in controlling the disease. 



On the formation of bacterial zoogloea on the roots of barley, II. Zikes 

 {Ztftrhr. (lesain. Brauw., 33 {1910). \o. 29, pp. 3.57-360) .—Atteutiou is calletl to 

 the formation on the roots of barley in bretnling ex|)eriments of a yellow, or 

 more rarely, a red zooglcea mass, consisting, for the yellow, of 3 species of bac- 

 teria, viz. Bacterium fiuore-sccns liquefaciens, B. herbicola aureum, and li. 

 rubrum, and for the red, of B. herbicola rubrum. 



It was found that these zoogloea on the roots check the growth of the barley 

 seedlings. 



Smut infection experiments with reference to breeding smut-resistant 

 varieties of barley, J. Broili {Natunr. Ztschr. For.^t u. Laudir., .S' {1910), No. 

 7, pp. 33.')-34.'i, figs. 7). — The author gives the result of infection experiments 

 with covered l)arley smut {Ustilago hordei teeta) and loose barley smut {Usii- 

 lago hordei nuda) on various varieties of barley. 



The conclusion is drawn that for the loose barley smut the breeding of 

 resistant varieties will be comparatively easy, but that for the covere<l smut 

 it will be more difticult on account of unknown factors, such as wintering and 

 time of planting, complicating the matter. 



