9 



ON THE CAUSE OF CANKER IN APPLE TREES. 



BY D. CAMERON, A.L.S. 



Soon after the establishment of the London and Caledonian Horticultural 

 Societies, the attention of horticulturists was directed towards devising a cure for 

 the Canker in Apple Trees. Since that time, many recipes have been given, but still 

 the evil is not much lessened, if we may judge by the appearance of many orchards, • . 



and more particularly in gardens. In orchards, the canker is not so prevalent, in 

 consequence of a spot in which the soil and situation being selected which are 

 suitable : but in gardens, however small or unfavourable the situation may be, 

 there are almost invariably apple trees, and consequently in such gardens the 

 canker is most common. That some of the recipes produced from the above 

 source were of considerable service there can be no doubt : the error with some 

 appears to have been in considering the canker as a primary disease, instead of 

 being produced by a vitiated or deficient state of the juices, occasioned by various 

 causes; such as soil, situation, &c. It is not likely that an effectual cure will 

 ever be found for the canker. Its effects, however, may be considerably miti- 

 gated by ascertaining its cause in the particular locality, and when ascertained, 

 to remove the cause as much as possible ; by which means the effects of the canker 

 will cease in a corresponding degree. Some varieties of apples are much more 

 subject to the canker than others, but the age of the variety does not appear to 

 be of so much consequence as an unfavourable soil and situation. The Downton 

 pippin will canker as well as the golden pippin. Having stated my opinion thus 

 far, it may be well for me to point out a few of those causes that have come under 

 my own observation, with the most likely means of remedy, leaving it to others 

 to supply deficiencies, and what has come under their own observation. 



One cause of canker is where the soil is naturally cold and damp, or made so « 

 by excessive rains in the spring. The growing season commences with warm, » ; 



mild, and cloudy weather, forcing the trees into blossom, and into leaf, before 

 the roots from the chilly state of the soil can emit fibres sufficient for the support 

 of their tops. All seems going on well, until either a few days of clear sunshine, 

 or a dry parching wind comes on. When this happens, by looking over the trees, 

 many clusters both of blossoms and buds, and also leaf-buds, will be found on 

 many trees drooping and withering ; every one of which, if not cut out with a knife 

 into the sound wood, are the seeds of future canker, and will sink deeper into 

 the branches of the trees, until they will frequently cause, in the course of 

 time, total decay of all that part of the branch situated above where the 

 canker commences. 



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