March, 1928] agricultural experiments 1927 23 



EUROPEAN CORN BORER NOT YET A MENACE 



For the fourth year careful studies have been made of the European 

 corn borer under New HampsMre conditions. 



The species entered the growing season of 1927, however, without 

 visible increase in numbers over those of the preceding three years. 

 Studies were begun and carried out by W. C. O'Kane in more than twenty 

 localities, including areas in which the insect had been present for at least 

 three consecutive seasons. In none of these was the pest found in 

 sufficient numbers to amount to anything. Only by extended search 

 could any individuals be discovered. Apparently, the density of popula- 

 tion of this insect under New Hampshire conditions remains stationary. 



While this makes the work under this project difficult, and some of it 

 impossible, it has an important bearing on the data published in Technical 

 Bulletin No. 33, which reported on the first three years' work. The sug- 

 gestion was then offered that the European corn borer, as observed in 

 New Hampshire, appeared, up to date, to be self-limiting in abundance, 

 possibly because of a marked inherent tendency to go through two 

 generations instead of one. Survival over the winter rested largely with 

 such individuals as were content with one generation. Individuals 

 representing the two-generation phase seemed unable to reach sufficient 

 development to hibernate successfully. A majority of the individuals 

 attempted a second generation, however, in spite of an unfavorable length 

 of summer season. 



The studies of this year, although seriously handicapped by lack of. 

 material to work with, seem to support the suggestion offered in Technical 

 Bulletin No. 33. If so, they are significant and may indicate that under 

 normal conditions the European corn borer will fail to become destructive 

 in most of New Hampshire. (Adams Fund.) 



EFFECT OF FERTILIZER ON SWEET CORN 



A series of nine plots has been studied for two years by F. S. Prince and 

 J. R. Hepler in which varying amounts of fertilizer have been used for 

 sweet corn. These plots, which are run in quadruphcate with eight check 

 plots, showed the following average yields of ears in pounds per acre for 

 the two years 1926 and 1927: Plot 1 (15 loads manure), 5,576 pounds; 

 Plot 2 (30 loads manure), 6,590 pounds; Plot 3 (15 loads manure, 400 acid 

 phosphate), 5,995 pounds; Plot 4 (15 loads manure, 800 pounds acid 

 phosphate), 6,105 pounds; Plot 5 (15 loads manure, 400 pounds 3-10-4 

 fertilizer), 6,154 pounds; Plot 6 (15 loads manure, 800 pounds 3-10-4 

 fertifizer), 6,235 pounds; Plot 7 (800 pounds 3-10-4 fertilizer), 5,108 

 pounds; Plot 8 (15 loads manure, 400 pounds 5-8-7 fertilizer), 5,920 

 pounds. Plot 9 (15 loads manure, 800 pounds 5-8-7 fertifizer), 6,290 

 pounds. 



The yields for 1927 were much lower than in 1926, due to the lack of 

 native fertility of the soil utifized and also to a very cool growing season. 



The effects of manure were more apparent in 1927 than in 1926, those 

 plots receiving 30 loads of manure being the heaviest yielders in 1927, 

 while the previous year this was not the case. The 400 pounds acid 

 phosphate treatment is the only fertilizer which has thus far paid for its 

 original cost. (Hatch Fund.) 



