Nov. 1. 1915 Potato Tuber-Rots Caused by Fusarium Spp. 201 



Table V. — Results of the inoculation of different varieties of potatoes with original and 

 reisolated strains of Fusarium eumartii 



Variety of potato. 



Number of 

 tubers. 



Incubation 

 period. 



Average 

 temperature. 



Percentage 

 of tubers 

 rotting. 



2932 



2947 



3O40>2947 

 3040 



2958 



Jersey Peachblovv 



Idaho Rural 



Early Rose 



People's 



Jersey Peachblow 



Idaho Rural 



Early Rose 



People's 



Netted Gem 



Idaho Rural 



People's 



Idaho Rural 



Jersey Peachblow, 



Idaho Rural 



Early Rose 



People's 



Days. 



100 

 100 

 100 

 100 



lOO 



100 

 100 



> =reisolation of. 



CONTROL INOCULATIONS OF POTATO TUBERS 



In order to ascertain whether any organism at random would cause a 

 decay of potato tubers under the conditions used to establish the wound- 

 parasitic property of the species mentioned, certain species of Fusarium 

 and other organisms inhabiting potato tubers were included in the exper- 

 iments. The following organisms were used for this purpose : F. martii, 

 F. solani, F. moniliforme, Verticillium albo-atrum, Sporotrichum flavissi- 

 mum, a species of Mucor, and a species of Rhizoctonia. The notes on the 

 effect of these organisms on different varieties of potatoes at sundry tem- 

 peratures are extracted from the several experiments and grouped accord- 

 ing to organism as a support of the method. It may be mentioned in 

 this connection that certain strains of F. radicicola (Nos. 2862 and 3319) 

 were found to be comparatively inactive under conditions identical with 

 those in which other strains were most virulent. 



INOCULATION OF POTATO TUBERS WITH CERTAIN SPECIES OF FUSARIUM 

 AND OTHER TUBER-INHABITING ORGANISMS 



F. solani 176; isolated in 1908 by Dr. Wollenweber at Dahlem, near 

 Berlin, Germany, from a potato tuber. Used for the original descrip- 

 tion of this species by Appel and Wollenweber (i,p, yy). Culture used, 

 2-months-old pionnotes on potato cylinder. After 51 days at an average 

 temperature of 21.5° C, this organism had attacked only 50 per cent of 

 but one variety. Pearl, and then only where a large cut surface was 



