DISEASES OF PLANTS. 243 



careful selection and preventive treatment of seeds, sparing use of nitrogenous 

 manures, suppression of weeds, rotation, and proper drainage. 



Observations on foot disease of wheat, Reuthkr (III us. Landw. Ztg., 33 

 {1913), No. 65, pp. 589-591). — The main substance of this report is contained in 

 the article noted above. 



Nematode disease of wheat, J. Appl (Wiener Landw. Ztg., 63 {1913), No. 69, 

 p. 787, figs. 3). — The author reports briefly on infection iind other studies car- 

 ried out on wheat in relation to Tylenchus tritici in Austria. 



The nematodes are said to invade the seedling fro4n the soil when very 

 young and to be carried upward with its growth, breeding in immense numbers 

 in the galls found in the heads. It is supposed, however, that they can infect 

 young plants only at short distances (probably not over 10 cm.) from the 

 original host plants. The galls, however, which are said to be almost the sole 

 means of spreading the infection, are distributed and sown with the seed 

 wheat, but it is suggested that by winnowing and other means they may be 

 largely removed, lessening greatly the danger from nematodes. 



A disease of peanuts, A. A. L. Rutgers {Dept. Landb., Nijv. an Handel 

 [Dutch East Indies'], Meded. Afdeel Plantenziekten, 1913, No. 6, pp. 5, pis. 2).— 

 A description is given of a disease of peanuts in Java that is believed to be 

 identical with that described by Zimmerman from German East Africa (E. 

 S. R., 19, p. 448). No organism has been definitely determined as causing the 

 disease, and experiments on its transmission and control have given negative 

 results. 



In addition to the peanut, the mungo bean {Phaseolus mungo), Dolichos 

 hiflorus, Crotalaria verrucosa, and probably Triumfetta rJiomhoidea are believed 

 to be subject to this disease. 



A contribution on chang-es in fleshy organs of plants due to micro- 

 organisms, L. Hauman-Merck (Ann. Inst. Pasteur, 27 (1913), No. 7, pp. 501- 

 522). — As the result of a study of the relations between several fleshy plants 

 and the organisms attacking them, the author states that in Argentina, as in 

 North America, winter potato rot is caused by Mncor stolonifer; that infection, 

 though ordinarily easy and quicl^: in case of contused wounds, is unlikely in 

 case of cut though unbruised tissues exposed to air, on account of rapid cica- 

 trization in such cases; that whatever prevents or hinders such cicatri- 

 zation in roots, tubers, leaves, etc., favors their immediate infection and 

 possibly the development also of substances unfavorable to suberization ; that, 

 therefore, attack of an organ through a wound or bruise seems to depend upon 

 the relative rate of development of the saprophyte in the superficial layers of 

 contused cells and of suberin in the layers immediately beneath. 



Leaf roll of potatoes, VI, G. Kock, K. Kornauth, and O. Bro^ (ZtscJir. 

 Landw. Yei'suchsw. Osterr., 16 (1913), No. 3, pp. 89-UO, pi. 1, fig. 1; ahs. in Bot. 

 CentbL, 123 (1913), No. 8, p. 200).— The authors give results of their 1912 

 studies on potato leaf roll, which are said to confirm those previously given 

 (E. S. R., 27, p. 447), The trouble is claimed to be due to a parasitic Fusarium. 

 which may invade the plant directly from the soil (primary infection), spread- 

 ing in the vascular bundles to or throughout the tubers and developing in 

 varying degree in the plants produced therefrom (secondary infection) ; or, 

 not reaching the tubers but interfering with their nutrition, may simply dwarf 

 these and successive crops therefrom. This trouble is claimed to be distinct 

 from some others which wither or crinkle the leaves. It appears either early 

 or late in the growing period. Numerous infection studies succeeded in re- 

 producing the disease. No close relation to weather has been determined. 



A list of the 1912 literature on this subject is appended. 



