12 



In the case of large boughs the canker-patch can sometimes 

 be cut out with a sharp knife or chisel. If care be taken 

 to cut down well into sound wood, and to protect the exposed 

 surface, the wound may completely heal over, and the bough 

 may thus be saved. 



2. Protection of Wounds. All cut surfaces should be 

 covered by a protective substance, such as coal-tar, Stockholm 

 tar, paint, painters' knotting, styptic or grafting wax. If 

 nothing better is procurable the surface may be luted with clay. 

 Eubbing over the surface with earth, a frequent custom, should 

 not be practised. 



3. Top Grafting. In certain cases, especially where the 

 variety is very susceptible, the tree may be cut back and top- 

 grafted with a more resistant variety, such as Bramley's 

 Seedling. 



4. Prevention of Woolly Aphis. Woolly Aphis, which not 

 only itself injures the tree, but frequently also introduces 

 canker, should be kept down. Instructions as to this pest will 

 be found in Leaflet No. 34. f 



5. Drainage. Apples are more liable to canker in heavy 

 subsoils and in damp situations. Where a wet, heavy soil is 

 present an effort should be made to drain it. In the case of 

 young trees growing down into an unsuitable soil, the trees 

 should be root pruned, and surface-rooting encouraged. On 

 exceptionally heavy and stiff land trees may sometimes be 

 planted on the surface and earthed up. 



6. Selection of Varieties. When planting a new garden or 

 orchard, varieties resistant to canker, and those which have 

 been found to do well in the locality, should be chosen. 



7. Sanitation. Spraying is practically useless, but in order 

 to reduce liability to infection all general sanitary measures 

 should be adopted, and diseased shoots and prunings should be 

 burned. 



APPLE AND PEAR SCAB. 



(Venturia inaqualis, and V. pirina.) 



Scab is probably the most general and most widely dis- 

 tributed fungus disease which attacks apples and pears. The 

 well-known black blotches or scabs on the fruit caused by this 

 fungus are familiar to everyone (Fig. 1 and 2).* 



In this country the disease causes an enormous amount of 

 damage in apple orchards and plantations, the annual losses 

 amounting to many thousands of pounds. During certain 



* The Ministry are indebted to Mr. E. S. Salmon for permission to 

 use Figures 2, 3 and 4. For more detailed description of the scab 

 fungus see Mr. Salmon's article in the Jour. Board Agric. (Vol. XV, 

 1908-9, pp. 182-195). 



| This leaflet can be obtained from the Ministry and also is included 

 in Sectional Volume No. 2, price lOd. 



