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ROSE TREE CANKER. 



BY GEORGE MASSEE, V.M.H., F.L.S., 



Principal of Cryptogamic Department and Plant Pathologist, 

 Kew Herbarium. 



This disease is of a physiological nature, and does 

 not depend on fungi or insects for the primary cause. 

 The appearance of the disease is well expressed by its 

 popular name ; the wood first shows signs of browning, 

 the bark cracks, and as the disease progresses the wood 

 is eaten away, or in other words becomes resolved into 

 a soluble substance which melts away, leaving large, 

 irregular gaps which often pass almost through the 

 branch. It is often most evident near the base of the 

 stem, near the junction of stock and scion. 



Unfortunately no cure is known, which is what 

 might be expected since the cause is unknown. 



The disease is more prevalent in certain districts 

 than in others, which suggests that substances present 

 in certain soils have something to do with the matter. 

 On the other hand, cases are known amongst other 

 plants where a similar disease results from the stock 

 acting prejudicially on the scion. 



Some varieties of Roses are more prone to canker 

 than others, Marechal Neil often suffers severely. 



