May29. iQio Fieldrot of Potato Tubers 309 



SUMMARY 



(i) Fusarium radicicola Wollenw. is the cause of a field blackrot of 

 potato tubers in southern Idaho. The disease is confined principally to 

 potatoes of the round type, such as Idaho Rural and Pearl. 



(2) F. radicicola is capable of causing a jelly-end rot of potatoes simi- 

 lar to the jelly-end rot of the Burbank group found in southern Idaho, 

 but under actual field conditions other factors are apparently in part 

 responsible. 



(3) Neither blackrot nor jelly-end rot makes any progress in storage 

 at or below a temperature of 50° F. 



(4) Seed pieces infected with blackrot will bring about infection in 

 the following crop. 



(5) F. radicicola is apparently well distributed throughout the desert 

 soils. 



(6) Blackrot may be controlled fairly well by planting potatoes only 

 on lands which have been in other crops for a number of years and by 

 providing good conditions for growth. 



