246 MAKING HORTICULTURE PAY 



apple growers is to continue to use 3-3-50 bordeaux 

 as in the past. 



" Probably many fruit growers have been alarmed 

 by Colorado station bulletin No. 131, on arsenical 

 poisoning of fruit trees. It is stated that in Colo- 

 rado apple trees suffer from a disease in which the 

 crown of the tree is girdled, the bark on portions 

 of the trunk dead and sunken, and most of the 

 roots dead. Dr. Headden, the station chemist, who 

 made an investigation of this trouble, concludes that 

 it is due to arsenic in the soil. When trees are 

 sprayed with arsenate of lead or arsenite of lime, 

 these substances eventually find their way into the 

 soil and accumulate there. 



" According to Dr. Headden, the alkali in the 

 Colorado soil renders the arsenic soluble, so that it 

 may be absorbed by the apple roots. That arsenic 

 in soluble form is extremely poisonous to plants is 

 well known. Dr. Headden analyzed the soil under 

 dying trees and found it to contain arsenic in dan- 

 gerously large quantities. He also found arsenic 

 in the wood of diseased trees. He holds that spray- 

 ing with arsenical compounds is responsible for the 

 death of the trees. 



" In the minds of eastern orchardists who read 

 this bulletin, the question will naturally arise. Does 

 this apply to orchards in the east? In the past it 

 has been assumed that, in our soils, the arsenical 

 compounds used in spraying retain the insoluble 

 form and so are not harmful to the trees." 



