340 SCIENCE AND FRUIT GROWING 



The presence of the disease was first noticed by finding a 

 large portion of cortex and cambium on the stems of some of 

 the trees to be yellow and rotten. The peri derm had not been 

 affected, so that the only external sign of anything being wrong 

 was the comparative flattening of the stem, owing to absence 

 of growth in the parts attacked. The parts affected were moist, 

 and possessed an unpleasant odour. The fungus had, also, in 

 most cases, penetrated to a considerable distance into the wood, 

 and could often be traced as having travelled along the wood or 

 cortex from one seat of activity, and then to have broken out into 

 a state of activity at some other point a considerable distance 

 away. The principal seat of attack seemed to be about half- 

 way up the stem, though in a few cases it extended nearly to 

 the roots, and in others some of the main branches were affected. 

 As a rule there appeared to have been no bark injury at the 

 seat of the attack, but, no doubt, an injury, too minute to be 

 visible, would be sufficient to allow of the entry of fungus-spores. 



The spread of the fungus was evidently very rapid, the portions 

 of the stem affected being often one to two feet in length, and 

 trees which had failed to show any signs of disease when 

 examined in the winter were found to be attacked to this extent 

 before the following midsummer. As soon as the disease had 

 spread right round the trunk, the supplies for the head of the 

 tree were cut off, and the leaves turned pale and dropped off 

 early; but up to this occurrence, the head of the tree continued 

 to appear perfectly healthy, and to make vigorous growth. In 

 the case of several trees where the disease had spread entirely 

 round the stem, and even in that of some where a foot or more 

 of the dead bark and cambium had been cut away right round 

 the tree, the trees came into leaf and fruited, and the fruit, 

 though poor, was saleable. These facts showed that, as a rule, 

 both the roots and the heads of the diseased trees were perfectly 

 healthy, the stems being the only parts affected. 



The oldest of the trees were about nine years old in 1896, 

 and these suffered to the extent of 55 per cent., those of inter- 

 mediate age suffered to the extent of 31 per cent., and the 

 youngest about four years old to only 12 per cent. As 

 regards varieties, the Victoria, Diamond and Greengage were 

 by far the heaviest sufferers. 



Throughout the attack, the trees were treated surgically, by 

 cutting away, where possible, such parts of them as were infested, 

 and tarring the exposed wood. In most cases where the disease 

 had not spread right round the trunk, the tree was saved, and 



