﻿18 BULLION. V 1146, L. S. DEPART Mi; NT 01 ACKK ULTTJRE. 



thr tubers from copper-sprayed plants were: LOrlO-50 spray, 17.9 

 jn"- cenl solids and 0.38 per cent nitrogen; 5-5-50 spray, 18.5 per cenl 

 is and 0.34 p .titrogen; 2-£-2|-o(! spray, liu.i per cent solids 



and 0.33 per cent nitrogen. The check tubers contained 18.3 per cent 

 solids and 0.33 per cent nitrogen. The tubers from the plots receiv- 

 ing the 2i- 2J-50 spray were highest, and those from the 10-10-50- 

 sprayed plots were lowest in solids. 



These results suggest the possibility that a certain proportion of 

 copper in a spray gives the maximum stimulating effect in this local- 

 ity and that a spray containing .a greater proportion of copper may 

 have a toxic rather than a stimulating* effect. Tubers grown at 

 Arlington Experimental Farm in 1920 from vines that were sprayed 

 with a 10-10-50 Bordeaux spray (p. 13) seemed to have no advan- 

 tages over the tubers from plants sprayed with a 1 4 50 Bordeaux. 

 It is, of course, probable that the stimulating effect of the copper 

 varies with the climatic conditions, variety of potatoes used, etc. 

 Tubers from vines in New Jersey sprayed with a 5-5-50 spray eight 

 times during the season were compared with tubers from vines 

 sprayed only four times with Bordeaux spray of the same strength. 

 The average data for four sets were 18.6 per cent of solids and 0.37 

 per cent of nitrogen in the tubers from vines sprayed eight times and 

 19.1 per cent of solids and 0.35 per cent of nitrogen for the tubers 

 from vines sprayed only four times. These variations are small and 

 may not be due to the differences in the spray applications. These 

 data also indicate that too much copper may have reached the vines 

 by the eight applications, whereas the amount of copper present in 

 the four applications was nearer the quantity required to give the 

 best protective effect or a maximum stimulation to the plants. 



INFLUENCE OF ENVIRONMENT ON COMPOSITION OF TUBERS. 



The following data were obtained during the 1919 season. Early 

 Rose tubers grown in Connecticut contained 21.59 per cent solids and 

 0.38 per cent nitrogen and the same variety grown at Arlington Ex- 

 perimental Farm contained 15.83 per cent solids and 0.33 per cent 

 nitrogen. Irish Cobbler tubers grown in Connecticut contained 22.28 

 per cent solids and 0.43 per cent nitrogen, while the same variety 

 grown at Arlington Experimental Farm contained 18.57 per cent 

 solids and 0.36 per cent nitrogen. Dibble Eussets from New York 

 contained 25.38 per cent solids and 0.39 per cent nitrogen and the same 

 variety grown at Mt. Carmel, Conn., contained 21.24 per cent solids 

 and 0.30 per cent nitrogen. Early Ohio tubers from Minnesota con- 

 tained 22.79 per cent solids and 0.48 per cent nitrogen and the same 

 variety from Connecticut, 20.52 per cent solids and 0.48 per cent 

 nitrogen. These results again suggest that the composition of the 

 tubers is influenced by the environment. 



Although these tubers were not grown from the same stock, the 

 results in each case seem to indicate that a northern tuber is higher in 

 solids than a southern tuber. This may explain why a northern grown 

 potato is a better seed potato than one grown in the South. The data 

 also show that there is a decided variation in the percentage of 

 solids in tubers of different varieties grown in the same localitj^. 

 In this connection it is interesting to recall the findings of LeClerc 

 and Yoder {27) who, working with wheat in four different parts 



