DISEASES OF PLANTS. 647 



By far the larger number of these varieties proved entirely susceptible to the 

 fungus. Of the 7 immune varieties found, 5 belonged to T. dicoccum and 2 to 

 T. ralgare. The enmiers as a group iiroved quite free from infection, although 

 some were quite susceptible. In none of the 9 species of Triticum tested was 

 complete immunity found, as in every case one or more varieties of each species 

 gave infection. 



On the rust of wheat (Puccinia glumarum), E. Sz^kacs (Wiener Lttndw. 

 Ztg., 61 {1911), No. 53, p. 609; abs. in Bot. CeiitU., 117 {1911), No. 21,, p. 633).— 

 The author gives the results of his investigations, in brief as follows: 



Those wheats which show no resistance to infection were found to be full of 

 rust as early as May 15. Neighboring plants were either only partially rusted 

 or wholly intact. This is held to show that the rust is transmitted not only as 

 primary infection (by secidiospores), but that it also breaks out as inherited 

 disease with favoring weather. The seed is the carrier of the infection, the 

 author believes. An improved seed stock obtained in 1906 by selection was 

 further sifted, so that from 214 elite stocks only 14 remained for breeding. 

 These stocks show decidedly less rust than those which spring from less 

 pure tyiies. By selective breeding it is evidently possible to control the rust. 

 The author appears to be a warm supporter of Eriksson's mycoplasm theory. 



A new root disease of malt, H. Sciinegg (Ztschr. Gcsam. Bra mo., 35 {1912), 

 Nos. 1, pp. Jf-l, fig. 1 ; 2, pp. 13-15, figs. 3). — This is a noteworthy case of dis- 

 ease ascribed to parasitism by a fungus said to be Rhizopus nigricans {Mucor 

 stolonlfer) . Illustrations and descriptions are given of the way in which this 

 fungus was found occupying the interstices between rootlets and sheaths in 

 the case of sprouts 3 days old, attacking both of these structures. It seems 

 not to enter the cells but to force its way between them, loosening the tissue 

 but not penetrating to the vascular bundles, or at least in most cases, to a 

 greater depth than 3 or 4 cell layers of the cortex. The cells are discolored and 

 distorted by the presence of the fungus. 



Investigations on Sclerotinia libertiana, Johanna Westerdijk {Meded. 

 Phytopath. Lab. Willie Cornmelin Scholten, 1911, pp. 5-26; abs. in Intemat. 

 Inst. Agr. [Rome], Bui. Bur. Agr. Intel, and Plant Diseases, 2 {1911), No. 5, 

 p. 1153). — This fungus is said to do considerable damage in Holland to lettuce, 

 beans, carrots, clover, and mustard. It passes readily from one plant to an- 

 other and does not appear to form biological races. Under favorable condi- 

 tions of growth the fungus does not seem to lose its properties as a parasite. 

 Infection is favored by ruptures in the cortex of the host and by a considerable 

 {(mount of atmospheric humidity. 



Cotton anthracnose, H. W. Barre {South Carolina 8ta. Rpt. 1911, pp. 23- 

 43). — In continuation of a previous account (E. S. R., 24, p. 741), the author 

 presents a progress report on his investigations relating to the cotton an- 

 thracnose, and the relation the fungus bears to distribution under field condi- 

 tions. The investigations indicate that the seed are one of the most important 

 factors in the distribution of this disease, and that where clean seed are used 

 one year's rotation will eliminate the disease. 



The vitality of the fungus in buried bolls and in the seed, and the vitality 

 of the mycelium and spores on the outside of the seed were investigated, and 

 it was found that buried bolls did not give any viable spores after the middle 

 of March, while bolls that had been allowed to lie on the edge of the field 

 against the fence contained the viable fungus up to September. The indica- 

 tions are that the fungus loses its vitality to some extent in the seed, although 

 not entirely so. 



A study was made of the progeny from seed of a number of diseased bolls 

 which contained one or more badly diseased or compact locks. The highest 



