DISEASES OP PLANTS. 849 



Collection and destruction of all fallen leaves in autumn and spraying with 

 2 per cent copper sulphate are recommended, as are also repetition of the spray- 

 ing in early spring and removal of the crop early in June hefore development 

 of the uredo stage is complete. 



Potato diseases, E. Henning (Kort oversikt over viktigarc smittosamma 

 sjukdomar hos potatisen. Stockholm: Wilhclmssons Boktr., 1915, pp. 28, figs. 

 8). — ^A brief discussion is given of Hypochnus solani, Phytophthora infestans, 

 Synchytrium endobioticum, Spongospora scabies, Fusarium, and such disorders 

 as bacterial ring rot, scurf, and leaf roll. 



Potato diseases (Bol. Agr. T^c. y Econ., 6 (1914), No. 11, pp. lOSl-lO^O).— 

 This is a brief discussion of direct and contributory local causes of potato dis- 

 eases or disorders, including fungi, bacteria, and nematodes, also of some pro- 

 tective measures as used in certain localities. 



Blight resistance in potatoes, W. S. Hill {Jour. Agr. [Nctc Zeal.], 8 (1914), 

 No. 4, pp. 370, 371, fig. 1; abs. in Internat. Inst. Agr. [Rome]', Mo. Bui. Agr. 

 Intel, and Plant Diseases, 5 {1914), No. 8, p. i088).— The author notes com- 

 parative experiments showing the superiority of the variety Gamekeeper over 

 Up-to-date, as regards resistance to late blight. He also discusses briefly some 

 other qualities. 



Fusaria of potatoes, C. D. Sherbakoff {New York Cornell Sta. Mem. 6 

 {1915), pp. 87-270, pis. 7, figs. 51). — The results of a monographic study begun 

 in 1911 of the species of Fusarium found on the potato are given. In this 

 work the fungi were studied in their Fusarium stages, no attempt being made 

 to determine their perfect forms. All the cultures were made from diseased 

 parts of the potato plant received from nearly every experiment station in the 

 United States, most of them isolated from tubers affected with dry or soft rots. 



In all the author recognizes 61 species and varieties of Fusarium, and In 

 addition he gives descriptions of 3 species of Ramularia which are said to be 

 often found on the potato and easily confused with species of Fusarium. The 

 following new species and varieties are technically described: F. cimeiforme, 

 F. udum solani, F. falcatum fuscum, F. caudatum solani, F. metacroum minus, 

 F. subulatum brevius, F. effusum, F. truncatum, F. lucidum, F. diversisporum, 

 F. biforme, F. anguioides, F. anguioides caudatum, F. arthrosporioides, F. 

 arthrosporioidcs asporotrichius, F. sporotrichioides, F. arcuosporum, F. ferru- 

 glnosum, F. sanguineum, F. sanguineum pallidium, F. bullatum, F. bullatum 

 roseum, F. angustum., F. redolens solani, F. lutulatum, F. lutulatum zonatum, 

 F. sclerotioidcs, F. sclerotioides brevius, F. oxysporum asclerotium, F. oxy- 

 sporum longius, F. oxysporum resupinatum, F. subpallidum, F. subpallidum 

 roseum, F. clavatum, F. discolor triseptatum, F. culmorum leteius, F. martii 

 viride, F. martii minus, F. solani cyanum, F. solani suffuscum, F. striatum, and 

 R. solani. 



In connection with the investigation, the author made some studies on en- 

 vironmental conditions and also the pathogenicity of the fungi. Extensive 

 inoculations of potato plants Avith all the Fusaria described in the memoir 

 yielded negative results, and would indicate that they are not wilt producers. 

 Several series of inoculations of potato tubers showed that a considerable num- 

 ber of species of Fusarium can cause more or less rapid decay of the tubers, 

 but that most of the species reported upon produced rot only after the tubers 

 had begun to sprout. The most common rot-producing organism, at least in 

 the eastern United States, is claimed to be F. coeruleum. The inoculation ex- 

 periments carried on with tubers seem to indicate that some species of the 

 fungi, while differing morphologically, may act very similarly so far as their 

 pathological conditions are concerned, and that others closely related from the 

 morphological standpoint differ widely in their pathogenicity. 



