300 MAINE AGRICULTURAL EXPERIMENT STATION. I907. 



DISCUSSION OF RESULTS. 



The profits from 6 heavy applications in a season like that 

 of 1907 are very apparent. These plots gave an increase of 

 45 bushels per acre at Foxcroft and jy bushels per acre at 

 Houlton over the yields of the better of the other 2 plots, while 

 at the prevailing prices of copper sulphate and lime the cost of 

 the extra materials used would not be over $3.00 per acre. 



The results from the 6 single vs. the 3 double applications 

 are somewhat contradictory. At Houlton the former gave 66 

 more bushels per acre while at Foxcroft the latter was the 

 better by 18 bushels per acre. This may be partly accounted 

 for because, as has already been stated, the modified Houlton 

 experiment was really 7 single sprayings compared with 3 

 double, while at Foxcroft there were 6 single sprayings com- 

 pared with 3 double sprayings with a single one added to make 

 up for excessive washing by rain. That a moderate number 

 of thorough sprayings applied at the right time are quite effect- 

 ive against late blight is well shown by the Foxcroft experiment 

 in comparing the results obtained from Plots 2 and 3. How- 

 ever, it should not be overlooked that additional thorough appli- 

 cations produced still better results, as is seen in the largely 

 increased yields from Plot 1 at both places. 



The per cent of rot in both fields is instructive in that it 

 corresponds quite closely with the ability of the machines used 

 to cover the entire foliage of a row. When compared with the 

 loss of 45.6 per cent from rot on the unsprayed check of the 

 adjoining dust experiment the amount of loss from rot in the 

 part of the experiment at Foxcroft is quite satisfactory. The 

 loss from rot of from 9.5 per cent to 23.5 per cent at Houlton 

 is entirely too high and might have been materially lessened if 

 the adjustments on the machine had admitted the raising of the 

 nozzles to sufficient height to cover the entire row with the 

 spray cone. However, it should be said that the work of 

 spraying this field was as carefully and thoroughly done as 

 could be under the circumstances. This is very evident when 

 we consider that on Plot 1, a measured acre, produced 420 

 bushels of sound potatoes and only about 5 bushels of these 

 were sorted out as below merchantable size. Moreover, out 

 of a large number of fields examined only one other was seen in 

 Aroostook County which was so well sprayed as this one. 



