DISEASES OF PLANTS. 537 



author describes the parasites f^ccurriug on some of the principal field, forage, 

 and garden crops, discussing them as far as possible in the systematic order 

 of the parasites. The first part of the book is devoted to plant parasites, while 

 the second treats of animal parasites. Following the description of each 

 species, the pathogenic r61e is indicated. A list is* given of the host plants, 

 the different parasites being classified according to the part of the host plant 

 attacked. 



Report of committee on fungus diseases for 1911, F. D. IIeald (Texas 

 Dept. Agr. Bui. 22 {1911), pp. 158-163).— The author lists as sufficiently abun- 

 dant to attract very general attention the following diseases: 



Powdery mildew of rose (Sphwrothccft' pannosa), rose leaf blotch (Actl- 

 nonema rosco), apricot scab or freckle (Cladosporium carpophilum), bacterial 

 blight of geraniums (species not yet determined), blossom-end blight of the 

 watermelon (cause not definitely known), bacterial canker of plum (species 

 not yet determined), and dieback or winterkilling of peach, plum, and apricot 

 (Valsa leucostoma). 



Remedial measures are suggested in connection with each disease. 



Suppression of plant diseases — Ireland and international action (Dcpt. 

 Agr. and Tech. Instr. Ireland Jour., 13 {1918), No. 4, pp. 661-664).— The suc- 

 cessful handling of the situation regarding international trade caused by the 

 recent appearance of black scab of potatoes in Ireland is cited and discussed 

 in its bearings upon a possible international arrangement in view of this and 

 related dangers, with a brief account of measures taken or contemplated to that 

 end. 



The powdery mildews — Erysiphaceae, G. M. Reed {Trans. Amcr. Micros. 

 Soc, 32 {1913), No. 4, pp. 219-258, pis. 4).— The author describes the general 

 characteristics of the Erysiphacejie, the group of fungi to which the powdery 

 mildews belong, and gives accounts of the development of the perithecium, host 

 distribution, biological specialization, economic importance, and pathological 

 effects of the powdery mildews. The classification of the species is treated at 

 length, keys for their identification being given. A host index and a bibliogra- 

 phy of literature are included. 



Ramularia, Mycosphaerella, ITectria, and Calonectria, H. W. Wollenwebeb 

 {Phytopathology, 3 {1913), No. 4, pp. 197-242, pis. 3). — The results of a mor- 

 phological and pathological study on the differentiation of species of fungi be- 

 longing to these groups are given. 



So far as pure culture investigations are concerned, the author found that 

 among the Ascomycetes septocylindrical conidia were wanting in Fusarium 

 proper but occur in certain sections of Nectria, Hypomyces, Mycosphaerella, 

 etc. Hypomyces is said to divide itself readily into several sections, which 

 are described. The genus Ramularia is said to embrace a number of wound 

 parasites. Septocylindrium does not differ in any material way from Ramu- 

 laria and they should be combined. 



According to the author, N. galligena, the cause of canker of fruit and other 

 deciduous trees in Europe, and C. graminicola, which produces the snowy mold 

 of cereals, are present in the United States. 



Notes on cultures of three species of Peridermium, G. G. Hedgcock and 

 W. H. Long (Phytopathology, 3 (1913), No. 4, pp. 250, 251). — Accounts are 

 given of infection experiments with species of Peridermium In which the alter- 

 nate hosts were determined. Sowings of aecidospores of P. incanspicuum on 

 Coreopsis verticillata showed infection, and the name for the fungus, based 

 upon this form,~ is given as Coleosporium inconspicuum n. comb. In addition 

 P. delicatulutn from Piniis rigida was found to grow on Euthamia graminifolia, 

 and the name C. delicatiiluni n. comb, is given for the fungus. The connection 



