204 Bulletin 176. 



young trees were set in each year to replace those which were killed 

 by certain appHcations, and in 1897 the trees being so large, every 

 other one in tiie rows was removed, thus reducing the number of 

 trees one-half. Figure 52 is a view of this experimental orchard 

 looking east down the rows in May, 1897 ; some of the different 

 applications put on the trees in July, 1896, are well illustrated here. 

 Figure 53 is a view of the same orchard looking soutli across it in 

 May, 1897. 



The literature of the insect was critically searched and the differ- 

 ent methods which have been recommended for combating it were 

 carefully considered. As many of the metliods were simply slight 

 variations of others, only representative ones were selected to be 

 thoroughly tested in our experiments. To these were added a few 

 new ones which occurred to us. We thoroughly tested about 

 twenty-iive methods for from one to three years each. 



In treating the trees each method would l)e applied to a row of 

 seven trees across the orchard, as shown in figure 52, where the first 

 row is treated with tarred paper, the third row with some white 

 substance, and so on. Beginning at the west end of the orchard we 

 would usually treat each of the first four rows of seven trees each 

 by a different method, and then leave the next two, or the 5th and 

 6th rows, untreated for a check experiment. The next four rows, 

 or the 7th, 8th, 9tli, and 10th rows, would then be treated, usually 

 each bv a different method, and the next two, or the 11th and 12th 

 rows, left untreated as checks. This method was continued on 

 through the orchard, duplicating each method at some other portion 

 of the orchard in order to give each as fair and complete a trial as 

 possible. All applications were made about the same time, usually 

 during the latter part of June, and everything was kept cultivated 

 during the growing season. The following spring every tree, treated 

 or untreated, would be carefully examined, and a note made of the 

 numbers and sizes of the borers found in each tree. All this 

 involved a great deal of time and labor each year, but nothing was 

 spared to give each method a thorough and scientific test. Most of 

 the work has been done by the writer, and every detail of it under 

 his direct observatioTi and supervision. We had no favorites among 

 the methods tested ; we tried t(j make each do all it was recom- 



