190 JOURNAL OF ECONOMIC ENTOMOLOGY [Vol. 3 



P. Holcomb are among the oldest of the typical commercial orchards 

 and have been sprayed rather heavily until recently. They do not, 

 however, show as much indication of the trouble as many of the 

 orchards which have been sprayed less and are located under less 

 favorable soil conditions. 



The Yakima Valley is located on the Snake River some distance 

 below Wenatchee and like its sister valley has a variety of soils and 

 a considerable amount of hardpan and seepage lands. Mr. William 

 Richards has sprayed his orchard eleven years, six or seven times per 

 year. Gibson Brothers, on similar soil, have been spraying for the 

 same length of time. These orchards are both of them above the 

 danger of seepage and very slight traces of alkali were visible and as 

 far as they were observed, the orchards have not suffered in any way 

 from their spraying. Mr. W. I. Huxtable's orchard which is on the 

 higher lands of Knob Hill, was investigated and a white, impenetrable 

 hardpan was encountered at about four feet, which seemed to be char- 

 acteristic of the soils of this region. The trees in this section showed 

 no apparent injury but on some of the older orchards the leaves were 

 slightly yellow and the fruit small, indicating a lack of soil fertility. 

 That it could not be due to any effect of the arsenic applied was evi- 

 dent from the fact that the same condition was observed on both apple 

 and peach orchards. At a little lower level than this a large number 

 of young trees just coming into bearing were observed to be dead or 

 dying. Most of the trees affected were Spitzenbergs, and many of 

 them had never been sprayed. In every case, however, the dead 

 trees were found on the lower sides of the orchards where the irriga- 

 tion water had been allowed to bank up against the roadway or ditch 

 bank. In many of these places the ground showed unmistakable 

 traces of alkali and the condition was apparently growing worse as 

 the newer orchards showed only slight traces of it. It seemed probable 

 that unless more care was used in handling the irrigation water in 

 the future, considerable areas would be injured in this way. 



A Ben Davis orchard was seen in this section that had been irri- 

 gated very late in the fall and as a result, almost every tree had been 

 winter killed on the southwest side, the injury extending in some 

 cases even to the upper sides of the limbs extending toward the 

 northeast. This was the most severe case of scalding that has been 

 observed and was considered to be caused by arsenical spraying until 

 attention was called to the fact that every single tree was injured 

 on the southwest side. 



The Payette-Boise Valleys in Idaho are the largest apple pro- 

 ducers and like other Snake River valleys, have considerable amounts 



