Spraying potatoes for early blight proved profitable each year during three seasons of experimentation. Three sprayings increased the net income per acre $3.20; five sprayings, $8.92; seven sprayings, $16.46 per acre.
About thirty different varieties of early and late potatoes were tested during each of the three years. Of the early varieties Irish Cobbler and Early Ohio gave the best yields; of the later varieties Prosperity and Rural New Yorker gave the highest yields.
The importance of seed selection was demonstrated by selecting high yielding hills in the field. The yield was increased 50 bushels of marketable tubers per acre by selecting the best hills as compared with the poorest hills. In selecting the best hills from both of these lots the following year the seed which had high yielding characters behind it still outyielded the poorer lot by 50 bushels of marketable tubers.
Planting late in April gave the highest yield in 1910. Plantings on May 16 and May 23 gave the highest yields in 1911 and 1912.
Greene, Laurenz and Maney, T. J.
"Better methods of potato production for Iowa: Results of three years’ investigations at Iowa Agricultural Experiment Station,"
Bulletin: Vol. 13
, Article 1.
Available at: https://lib.dr.iastate.edu/bulletin/vol13/iss149/1