DISEASES OF PLANTS. 263 



A new disease of potato, S. Gueraud de Laharpe [Jour. Aijr. Vrdt., ii. scr., 3 

 [1902), Xu. 15, pp. 4S1, 482).— A. summary is given of the investigations of Delacroix 

 on the bacterial disease of the potato due to Bacillus solanirtcold. This disease has 

 been inider investigation for some time. For its prevention the planting of s<jund 

 tubers and 4-year rotation, the use of entire tubers which are to be treated before 

 l)lanting with a 1:20 solution of formalin, and the planting of the potatoes as late in 

 the season as possible, allowance being made for the harvesting of the crop, are 

 recommended. 



A new disease of potato, K. Roger [Ker. Hart. [Far is], 74 {l!->02), No. 4, 1>P- 94, 

 95). — A sununary is given of the ])revious publications of Delacroix and others 

 relating tn the bacterial disease of jiotatoes caused by Bacillus solanincola. 



The brown disease of potatoes, ('. E. Bessey {Science, n. ser., 15 {1902), No. 312, 

 p. 274). — For several years the potato crop of Nebraska is reported as having been 

 seriously damaged by a disease which caused the tibrovascular bundles of the tubers 

 to turn l)rown. Tliis disease is said to be widely distributed in America and P^urope, 

 but as yet no satisfactory cause for it has been discovered. A series of experiments 

 was begun in the laboratory of the University of Nebraska to determine, if possible, 

 what produced this disease. Cultures made from diseased tubers soon showe<l tufts 

 of mold filaments projecting from the diseased bundles. These, upon development 

 of their fruits, proved to be the filaments of Stysanus stemonitex. Repeated experi- 

 ments were made in which, in every case, cultures of the brown bundles produced 

 the fungus, while those which were not discolored were wholly free from the fungus. 

 Tubers examined from a number of parts of Nebraska, as well as from other States, 

 showed the presence of the fungus. These experiments have been contiimed for a 

 munberof months, and it is believed that Stysanus stemonites is the cause of the disease. 



The snow mildew, V. Sorauer {Ztt^chr. Pflcmzenkrank., 11 {1901), No. 4-5, pp. 

 217-228) . — Under this name the author describes a disease of rye which he says 

 has been known for a long time, but has been given but little consideration. The 

 cause of the disease is said to be Fumrinm nivale. The history and systematic rela- 

 tionship (jf the disease is discussed at considerable length and the action of the fungus 

 wlieii freely growing in the field and in inoculation experiments is described. 



A new parasite of sugar beets in Egypt, V. Mosseri {Ann. Ecole Nat. Agr. 

 Montpellier, n. ser., 1 {1902), No. 3-4, pp. 310-319). — Orohanche tinctoria, or 0. liitca, 

 as it is sometimes called, is reported as growing parasitically on the roots of sugar 

 beets in Egypt. The plant has long been known in that country, but was first 

 noticed as occurring destructively on beets in 1900. 



Diplodia cacaoicola, a parasitic fungus on sugar cane and cacao in the 

 West Indies^ A. Howakd {Ann. Bat., 15 {1901), No. GO, jip. 683-701, ph. ;.-').— While 

 pursuing tlie study of the rind fungus of sugar cane, reported in E. S. R., 1.'!, ]>. 4H(i, 

 the author freciuently distinguished a second fungus which exhil)ited little difference 

 fi'om that which is considered the Melanconium stage of the rind fungus Iriclio.vjluvria 

 xdccjiori. This disease is connnonly called the rind fungus or root disease wherever 

 it occui's, and subsequent investigations have shown that the predominant fungus on 

 canes examined from a number of localities is identical with that just mentioned, and 

 experiments were undertaken to develoj) the fungus under artificial con(liti( ms. Pure 

 cultures were succes.sfully grown, and inoculations made showed that the fungus was 

 truly parasitic on the sugar cane. 



An investigation of the fungus found on the pods and branches of the cacao tree 

 showed that, so far as the characters of the pycnidia and spores are concerned, it 

 agrees exactly with the form described on the sugar cane. Artificial cultures from 

 the cacao were carried out in a similar manner to those made with the sugar-cane 

 fungus, jmre cultures being made from the fungus obtained from the pods as well as 

 from the cacao trees. The infection experiments showed that the fungus could live 

 as a parasite on the cacao pods and is a dangerous wound parasite of the tree itself. 



