24 EXPERIMENT STATION BULLETIN. 



They were compared with standard lime-sulphur solution, 1 to 40, which 

 gave better results than any of the substitutes. 



ARSENICALS 



Calcium Arsenale. In 1918 calcium arsenate was used in three 

 orchards including Stark, Baldwin, Ben Davis and Northern Spy. It 

 was used wdth dilute lime-sulphur and without the addition of lime. 

 It caused rather severe foliage injury on Ben Davis, considerable injury 

 on Northern Spy and slight injury on Stark and Baldwin. Codling 

 moth injury was quite severe on the check trees of Ben Davis and Stark 

 but where calcium arsenate was used the control was very good. 



In 1919 calcium arsenate was used on Stark. Lime was added to 

 prevent burning. It caused less injury than when used without lime 

 but the control of codling moth was not so good as in 1918. 



Magnesium Arsenate. This material was used on Stark and the re- 

 sults were very unsatisfactory. Foliage injury was very severe and the 

 insect control was not satisfactory. 



Lead Arsenate. This material has given uniformly good results 

 wherever used. There has been very little foliage injury and insect 

 control has been satisfactory. Corona dry lead arsenate has been used 

 in nearly all the experimental work reported in this bulletin. NuRex- 

 form brand was also used in 1919 and it gave satisfactory results. 



Table IX summarizes the results of the counts for each plot in the 

 various experiments. 



