ea Pictorial peaqtiqal frvit growing. 



Higher up, at e, is seen another wound with the canker fruits showing, and 

 at various points on the side branches other wounds may be seen. 



It will be well to glance at a few causes of canker before coming to 

 remedies. In my opinion there are three which eclipse all others, and I 

 will place them in what I consider to be their order of infamy : — 



1. Unsuitable soil, either from poverty or peculiarity of variety. 



2. Predisposing injury by aphides, birds, or man. 



3. Rubbing by crossed branches. 



If the soil in which fruit trees are grown were systematically cultivated 

 and manured (see previous chapter), there would be two-thirds" less canker 

 than there is now ; and if growers were careful in choosing varieties the 

 proportion of unhealthy tices would be still less. 



It is impossible to prevent all external injury to fruit trees, but by 

 keeping down aphides and exercising care in handling at planting and 

 pruning time the damage is reduced to a minimum. It is quite possible to 

 avoid all injury by branch-rubbing (see " Pruning "). 



Can canker be cured when it has got a firm hold ? This is a question that 

 Is usually answered in the negative. Personally, I protest against so swift a 

 surrender of the position. It is easy, of course, to " let things slide," but it 

 is not very profitable, nor altogether creditable either. There are doubtless 

 cases in which the enemy is master of the situation, but there are certainly 

 a great many others in which he could be met and defeated. 



If a fruit grower has a number of trees which canker badly, and they 

 prove to be of one or two particular varieties, he will be justified in con- 

 cluding that the soil does not suit those sorts. If the trees are old the best 

 thing will be to get rid of them ; if they are young he may graft them 

 with a stronger sort (see chapter on " Grafting "). In Nottinghamshire I 

 have seen trees of Ribston Pippin, so badly cankered that the trunk was 

 nearly girdled, brought back to health and vigour by grafting them with 

 the strong and hardy variety Bramley'f Seedling. The great gaping wounds 

 on the bole have completely healed. 



Where canker is pretty genera], affecting nearly all the varieties, it is 

 safe to assume that there is something wrong with the soil. It is perhaps 

 undrained ; or it is poverty stricken. Want of drainage accounts for an 

 enormous amount of loss from canker. Fruit plantations on a slope are 

 usually drained naturally; but on a plateau, or in a valley, pipes are 

 frequently wanted. If pipes are laid 30 inches deep in strong land, and 

 the soil above is. bastard trenched and winter ridged, the ground will be 

 so much warmer, sweeter, and more fertile that the trees are bound to be 

 benefited. If the soil is poor it should be fed in the way described in a 



APPLE AND PEAR SCAB (seepages 69 and 79). 



A., small scaiied Apple, natural size, showing a, blaclc spots ; b, depressed brown or black patch 

 with cractcs ; c, point of advance by Fungus, prostrate hyphce or mycelium beneath the slciii 

 of fruit. 



B, section of a bit of the fruit tissues where the sldn was broken through by the Fungus, showing 



d, slcin (epidermis) turned up; e, spores of Fungus (Fusichadium dendriticum) in position; 

 f, mycelium of Fungus ; g, cells of Apple. v 



C, leaf of Apple tree, natural size, showing h, blaclc dots and blotches caused by Fungus. 



D, Fungus broken through membrane of Apple tree leaf: i, spores ; j, mycelium. 



E, smull scabbed Pear, natural size, showing depressed patch caused by Fu7igus, with scabbed 



places where this has broken through the skin. 



F, the Fear Scab and Cracking Fungus, Fusichadium dendriticum or pyrinum : I, spores ;mt 



mycelium. 



