TEMPERATURE AND HUMIDITY STUDIES OF SOME 

 FUSARIA ROTS OF THE IRISH POTATO ' 



By R. W. Goss 

 Assistant Plant Pathologist, Nebraska Agricultural Experiment Station 



INTRODUCTION 



The ability of Fusarium oxysporum Schlect. to cause a rot of the 

 potato tuber has been clearly demonstrated by a number of workers. 

 The influence of temperature on this disease has been reported in a 

 number o;f papers, but the experimental evidence as a whole is rather 

 meager, usually only extreme temperatures being vtsed. The effect of 

 moisture on the progress of the disease, except under conditions of 

 extreme dryness or saturation, has received practically no attention. 

 It was with the purpose of determining the relation of temperature and 

 humidity to the progress of potato tuber-rots caused by Fusaria that 

 the following work was undertaken. 



HISTORICAL 



The association of Fusaria with storage-rots of the Irish potato (Sola- 

 num tuberosum L.) has been a matter of common observation by most 

 workers in plant pathology from 1842 to date. Several species of the 

 form genus Fusarium Link have been described as causes of potato 

 tuber-rots, by Von Martins {12), Reinke and Berthold {18), Schacht 

 (jp), Pethybridge and Bowers (14)," Longman {10), and Sherbakoff {20). 

 The fact that Fusarium species could produce a rot of the tuber was 

 demonstrated by Pizzigoni {15) and Wehmer {24, 25), who described 

 the species they worked with as Fusarium solani (Mart). Frank (6), 

 De Bary (2), and others considered that the Fusaria were unable to 

 produce a rot of the tuber. In most of the earlier papers, F. solani, or 

 some species thought to be a synonym of it, was given as the causal 

 organism. 



Owing to the absence of clearly defined species in all the literature 

 previous to Appel and Wollenweber's (i) monograph on the form genus 

 Fusarium in 191 2, no attempt will be made to review in detail the earlier 

 reports of potato tuber-rots caused by Fusaria. 



Fusarium oxysporum was considered by Wollenweber (27) to be a 

 strictly vascular parasite producing a wilt of the potato vine but not 



• Published with the approval of the Director of the Nebraska Agricultural Experiment Station. The 

 paper is based upon experimental -work undertaken at the Michigan Agricultural College in 1914-15, and 

 at the University of Wisconsin in 1916-17. 



' Reference is made by number (italic) to "Literature cited," p. 77-79. 



Journal of Agricultural Research, Vol. XXII, No. 2 



Washington, D. C. Oct. 8, 1921 



zb Key No. Nebr.-3 



(65) 



