46 



cavities filled with gum. The inner bark becomes watery and 

 more or less rotten, and has a very disagreeable, fetid odour. 

 As the malady developes, the demarcation between the healthy 

 bark and the diseased patches becomes very apparent. The 

 plant endeavours to throw oh the disease and a separative 

 layer is formed between the healthy and diseased portions. 

 The patch of diseased bark thus delimited, dries up, the edges 

 break away where the separative layer is formed and gradually 

 curve up in drying. Finally the patches of diseased bark are 

 thrown off. The death and decay of the tissues caused by the 

 disease extend through the bark and apparently for some 

 distance into the wood. The cambium layer, the most vital 

 part of the tree, situated between the bark and the wood, is 

 destroyed, and when the bark is thrown off there is no possi- 

 bility of new bark growing over that portion. The patches of 

 bark which first become diseased, are irregular in shape and 

 vary greatly in size, but are usually from one to f >ur inches in 

 diameter. The exudation of gum occurs principally in the 

 spring or in early autumn, after the rainy season, while deli- 

 mitation and detachment of the bark usually take place during 

 the summer or winter. 



As the disease progresses, gam exudes on other portions of 

 the bark which are in turn thrown off. It is quite common 

 for a circle of bark surrounding an old diseased spot to become 

 affected and be thrown off, thus enlarging the spot. The 

 malady gradually spreads in all directions, but principally 

 down on the main crown roots and around the trunk in a 

 lateral direction. Year after year other portions of bark be- 

 come affected, until the tree is entirely girdled and thereby 

 killed. In maligant cases the disease runs its course and kills 

 the tree in two years or less, while in mild cases the growth of 

 the tree is scarcely affected, and in a few yea -s the wounds are 

 often completely covered with the new growth from the sides. 

 The destruction of the bark on the trunk does not usually 

 extend over one or one and a half feet above the ground, but 

 occurs on the roots for some distance below the surface. 



Trees affected with foot-rot appear at first as if they were 

 suffering from lack of nourishment. The foliage becomes light 

 yellow and scanty, the leaves developed being smaller than 

 usual ; the tree bears considerable fruit, apparently of normal 

 size and good quality. This abundant fruiting is in marked 

 contrast with blight where a profuse bloom is formed, but 

 very little fruit set. In trees suffering from this disease the 

 small limbs die first, but as the malady progresses large limbs 

 succumb, thus giving the tree a ragged appear,) nee. Again in 

 marked contrast with blight and with severe cases of die-back, 



