POTATO EXPERIMENTS IX 1903. I47 



Spraying. On the average, the yield of the earlier varieties was 

 one-third greater from the sprayed rows and in the case of the 

 late varieties one-half greater. 



The yield of merchantable potatoes from the early varieties 

 was practically the same, whether dug in September or October. 

 The yield of the late varieties, both sprayed and unsprayed, was 

 a third greater at the later date. 



It is planned to continue this experiment in the season of 1904. 



Bug Death vs. Paris Greex ox Yield of Potatoes. 



PixE CoxE vs. Lump Lime for Bordeaux Mixture. 



A four acre field on the college farm of fairly uniform soil 

 was prepared and planted to potatoes. The soil is a medium 

 heavy loam with heavy clay subsoil. The field had been in 

 grass since 1898 until it was plowed in the fall of 1901. In 1902 

 it was quite heavily dressed with barn manure and planted to 

 silage corn. About 600 pounds per acre of a high grade com- 

 mercial fertilizer was applied in drill at time of planting the corn. 

 Ihe yield of silage corn was about 14 tons to the acre. Because 

 of the backward season the ears were not filled when the com 

 was harvested. The land was plowed in the fall of 1902, 

 thoroughly worked with the Clark double action cutaway harrow 

 in the spring of 1903, and ten days before planting was cross 

 plowed and reworked with the cutaway harrow, so that at time 

 of planting an excellent seed bed had been prepared. ^Nlay 14 

 and 15 the field was planted Vv'ith Aroostook county grown 

 Green ^^lountain potatoes, with the Robbins planter, about 6 

 inches deep, in rows 32 inches apart and 12 inches in the row. 

 About 1000 pounds per acre of a fertilizer carrying 3 per cent 

 nitrogen, 7 per cent available phosphoric acid and 4 per cent pot- 

 ash was applied in the row by the planter. During the season 

 the field was kept cultivated and fairly free from weeds. The 

 potatoes were all sprayed seven times, June 19, June 25, July 3, 

 July 13, July 17. Aug. 13, and Aug. 19. Part of the field was 

 sprayed with Bordeaux mixture and Bug Death at the rate of a 

 barrel of Bordeaux and 25 pounds of Bug Death per acre to each 

 application. A second part was sprayed with a barrel of Bor- 

 deaux mixture and a half pound of Paris green for each applica- 

 tion, excci)t that on July 13 the Paris green was used at the rate 



