766 



THE MONTHLY BULLETIN. 



guise. Owing to the fact that the pear is very prolific aiul is other- 

 wise very free from troubles, if there were no such disease as pear 

 blight pears could be produced in such enormous quantities that there 

 would be no profit in growing them. But blight will continue to keep 

 the production limited, and there will always be a handsome profit in 

 pears. 



A CASE OF ARSENICAL INJURY TO APRICOT TREES. 



By Geo. P. Weldon, Chief Deputy State Commissioner of Horticulture. 



It has been known for some time that arsenic applied to trees in the 

 form of lead arsenate, Paris green, etc., for the control of insect pests, 

 may accumulate at the crowns and a sufficient amount become soluble 



^r^r-.C» 



^^*-^^li% 



v^>\ 











K 





Fig. 403. — Dead roots near the crown of young- api-icot tree, due to arsenical in.lury. 



(Original.) 



to corrode the bark and girdle the trees. Dr. W. P. Pleadden of the 

 Colorado Experiment Station and Prof. D. B. Swingle of the Montana 

 Experiment Station have given in publications from their respective 

 stations much analytical and experimental proof of such injury. 



Typical cases of this damage to orchard trees may be recognized in 

 advanced cases by the following symptoms : foliage small and yellow, 

 or at least unnaturally colored early in the season. Usually there is 

 a very heavy crop of fruit, also highly colored. Longitudinal cracks 

 often occur in the bark which may be discolored an unnatural yellow. 



