CAN 



CAN 



tliseasc, from Uk' lnuls of trees l)ting a lateral 

 j>ro2:inv, and consequently havinii' a more exact 

 reseuil/iance t<j ilieir parents, he'uiy, thereby 

 " more liable to llic diseases gradually acc|uired 

 or inereasedh\- iheinHiicnce of soil or climate ;" 

 not liavnic the ijrohahililv of iinprovenienl, as 

 in those propagated in other modes. 



The disease is, however, tapuhle of being 

 produced in other ways. It is very a]it lo l>e in- 

 duced in diirereiU sorts of trees by the destruc- 

 tion of the bark, by cxlcmai violence, as a blow 

 of the spade wheie digging is performed without 

 sufficient caution. 



In apple-trees J\lr. Forsvth lias found it very 

 liable lo be caused bv the want of due allenlion 

 in pruning, the leaving of the fool-stalks of 

 the fruit on the trees; and certainly by the 

 bruises prod\iccd bv ladders in gathering the 

 fruit. Too tight nailing, I'rom the pressure of 

 the shreds on the shoots. The wetness of the 

 autumn season, by preventing the young wood 

 from becoming well ripened, when succeeded 

 bv sharp frost, often ]iroduces the disease, from 

 the youns shoot beino destroyed and left on the 

 trees. 'I'Tieir being left in this way has like- 

 wise much tendency to promote its increase. 

 It is also suggested that the buds' being eaten and 

 destroyed b\" birds or insects produces the same 

 consequences. 



Mr. Forsyth well remarks, that by leaving 

 the dead wood on the trees during the sununer, 

 the flisease is infaliil)ly brought on; and that 

 when it is continued for years they are wholly 

 destroyed. He advises their being cut olT the 

 latter end of April, or in tiie following month, 

 when their progress can be ascertained, and to 

 ])erform the operation three, four, or more t)nds 

 below the seemingly diseased part, as the affec- 

 tion often extends much further in the heart of 

 the shoot, than it seems to do on the outside. 

 The cutting should be carried so far down that 

 the rusty colour disappears, and there Is only the 

 soiuid white wood. 



Some contend that this disease is produced in 

 all sorts of trees, solely by the quality of the 

 soil, as where it is of the sour clayey, shingly, 

 or gravelly kind; but Mr. Forsyth found that in 

 these, though he allows that fruit-trees succeed 

 best in mellow loams, the roots were not in the 

 least affected where the branches were very 

 greatly diseased. It is asserted tliat the canker 

 constantly proceeds from the brauehcs and stem 

 to the roots, but iiever in the contrary direc- 

 tion. 



When trees are very much affected in conse- 

 quence of large wounds, it is advised, by the 

 above writer^ to pare off all the mfectcd parts ot 



the hark with a draw-knife; and at the inner 

 white bark is frequently diseased, having a 

 dotted ajjpearance, it should likewise be wholly 

 removed, as, w hen any is left, it extends itself 

 afresh. And when tlie trunk is become hollow 

 it is reconuucndid to roinid out the decayed 

 parts, and then to ajiply the composition wliich 

 he Ins rcciininiendcd in a lupial state, with a 

 brush, over the |)arts Irom w Inch tlie cankered 

 bark or tiead wood has been removcil, shaking 

 the pow dcr of wood-ashes and burnt bones over 

 it. In this way the disease will soon be re- 

 moved, and the hollow trunk in lime filled 



But when the stem is greatly decayed it is 

 necci'sarv lo open the earth, and remove all the 

 rotten parts completely ; ihen tilling uj) the 

 parts with a mixture of the coniposuinn and 

 clav, as used in grafting, to within a tew inches 

 of the surface grr)Uiui, forcing it well in by 

 treading, the surface being made sloping from 

 the tree, to convey off" the wet. The whoU 

 should tlien be made level w ith mould. 



Alter having inanasjed the old wounded parts 

 in this way, tlie old bark is advised to be exa- 

 mined, and, w hen found wrinkled or cracked, 

 on the oiUside, pared off' with a draw-knife, 

 and the composition applied as above ; which 

 produces a fine smooth bark underneath it, the 

 plaster with the old bark peeling oflT in the suc- 

 ceeding w inter or spring ; at this time, all the 

 old bark remaining in the hollows, being re- 

 moved by a wooden or bone knife. After this, 

 the parts from which the bark has been scraped 

 off" sliould be thinly coated over with a liquid 

 composed of cow-dung, soap-suds, and urme. 

 This remains till the new bark is formed, when 

 it is discharged of itself, during the summer or 

 following spring, leaving a line new smooth 

 bark. The same operation may be re|)eated in 

 the ensuing sprina' if there should be occasion ; 

 by which Uie whole of the old diseased bark 

 may-be slouuhed off", and the tree kept in a fine 

 licalthy state and perfect order. 



In the prevention of this vegetable affection, 

 much care is necessary in the pruning and other 

 management of the trees. All the ends of 

 diseased shoots should invariably be removed, 

 as well as the old fruit-stalks and dead stubs 

 cut away. 'i'he appearance of gum on the 

 stems or branches of trees indicates their being 

 attacked with the canker. 



Common white paint is sometimes made 

 use of as an application for the removal of 

 canker. When this substance is employed. 

 Dr. Darwin has suggested that it may pro- 

 bably be rendered more destructive to insects. 



