Hi N. H. Agr. Experiment Station [Bulletin 256 



and the average price per bushel is combined with the average cost of 

 production, it will give the net price per bushel to the grower. 



In determining the best policy to follow in recommending further 

 development of potato markets in New Hampshire, the advantages or 

 disadvantages in production and marketing need to be balanced with 

 one another. A comparison of potato production costs in different 

 sections of the state has already been made and published in Station 

 Bulletin 239. The present investigation will round out the picture of 

 the potato industry in New Hampshire. (Purnell Fund) 



Temperature Affects Potato Diseases 



That temperature is to a large degree responsible for the difference 

 in behavior of potato diseases in northern and southern New Hampshire 

 is indicated by greenhouse experiments conducted by 0. Butler. 



Healthy plants and plants affected with mosaic and leaf roll are 

 grown in one case at a mean temperature approximating very closely 

 that of the certified-seed producing area of the state, and in the other 

 case at a mean temperature approximating that of southern New Hamp- 

 shire. 



As was to be expected the mosaic plants grown at the higher tem- 

 perature showed only mild or obscure symptoms of disease, while 

 those at the lower temperature were conspicuously affected. The leaf 

 roll plants showed the symptoms characteristic of this malady better 

 at the low than the high temperature. The healthy stock grown at 

 the lower temperature were much finer and thriftier plants than those 

 grown at the higher temperature, behaving in this respect much like 

 plants grown in the field under similar temperatures. 



The mean number of tubers per plant was not affected by the tem- 

 perature, and the yield of the mosaic and leaf roll plants was better 

 at the higher temperature — results which the condition of the plants 

 during growth would have led one to expect. The healthy plants 

 yielded better when grown at the low temperature, and this despite 

 the fact that the sprouts were slower coming through the ground. In 

 other words the growth of the crop is faster at low than high tem- 

 peratures. 



Burgundy Mixtures Studied 



Foliage is scorched when the proportion of copper sulphate to so- 

 dium carbonate (crys) in one per cent Burgundy mixture is reduced 

 to as low as 1:0.5, finds 0. Butler. Mixtures of 1:1 and 1:1.5 pro- 

 duced no injury on beans, whet her exposed to the weather or pro- 

 tected, while a mixture of 1:1.84 caused very slight damage. With 

 apples, increasing the amount of sodium carbonate delay ed the ap- 

 pearance of injury, though eventually the total amount of damage was 

 much the same for all mixtures except the most injurious one, 1:0.5. 



Experiments on the prevention of deterioration of Burgundy mix- 

 ture have been continued. A one-per-cent 1:1 mixture, which is acid 

 when first made and becomes neutral on standing in an open vessel, 

 and the copper precipitate, dense and heavy, may be preserved in- 

 definitely by citric and tartaric acids, the experiments so far carried 

 out indicating that the former is probably to be preferred. 



