Agricultural Research in New Ha 



mpshire 



29 



survived the winter, would 

 grow in the same manner as 

 volunteer plants and show 

 infection. 



In the spring of 1942, 

 ring rot free Green Moun- 

 tain seed was planted in soil 

 infested the previous Octo- 

 ber. Ring rot infected tubers, 

 saved over winter, were 

 placed in the soil in hills with 

 healthy seed. At the present 

 time, July 29, 1942, none of 

 the plants growing in the 

 soil infested in the fall of 

 1941 or the spring of 1942 

 show any of the symptoms 

 of ring rot. 



In other tests, soil to 

 which macerated ring rot in- 

 fected tubers had been added 

 was placed in 50 six-inch 

 pots. One half of the pots 

 were placed in the green- 

 house and the other half set 

 in the soil outside and ex- 

 posed to actual winter wea- 

 ther. Thirty days later (Jan- 

 uary 10) and on the tenth 

 day of each of the months of February, March, April, and May five 

 pots from the greenhouse lot and five pots from those left outside 

 were planted with ring rot free Green Mountain potatoes. The plants 

 growing in the pots were examined regularly for symptoms of the 

 disease and in no case did ring rot develop. 



Tubers produced by the plants grown in the infested soil have been 

 saved and will be planted to determine whether the pathogen is present in 

 the tubers but did not produce ring rot symptoms in the plants before 

 the tubers were harvested. 



The results so far indicate that plants grown from healthy seed do 

 not readily become infected when planted in ring rot infested soil. The 

 length of time that the organism remains viable in the soil has yet to be 

 determined. (M. C. Richards) 



Temperature Variations in Potato Bins 



This project was originally planned to study temperature variations 

 at the top and bottom of potato bins and to note losses in tubers stored 

 under different conditions. The size and depth of bin and the effect of 

 free air space above the bin on temperature variations were considered. 

 Likewise, the positional effect on the potatoes in the bin on sprouting 

 and weight losses was studied. Early in the experiment it was observed 



Plant Infected with Ring Rot, Show- 

 ing Wilting Leaves on One side 



