39 
doubtless of a fungoid nature, are formed upon the young twigs, and 
In some instances become confluent, ultimately leading to the disinte- 
gration of the bark, followed by an exudation of gum at the affected 
parts. The buds decay and become infested with thrip or other insects 
to a greater or less extent, the bark becomes shrivelled, and the 
affected shoot dies. As a general rule, the lowest branches are affected 
before the upper. Sometimes the tree is killed by the first attack, but 
usually, on the approach of autumn, new leaves are produced towards 
the tips of the young shoots. Although in many cases the new leaves 
are attacked by a fungus, the plant seems in a fair way for recovery, 
but in the following spring the same sequence of incidents occurs, and 
sooner or later the tree dies. 
All the symptoms enumerated afford evidence that the constitu- 
tion of the plant has become weakened ; the vital processes are not 
properly performed, so that the plant is not only unable to endure 
sudden changes of temperature, but is more liable to the attacks of 
fungi and insects, while it has less power to resist them. 
Amongst the facts which might be adduced in support of this 
view the following may be selected: (1) The simultaneous appear- 
rance of the decay in various parts of the colony, its rapid extension, 
and uniform results. (2) The similarity of results exhibited in other 
countries where the peach has received similar treatment. (8) Trees 
are destroyed at all periods of growth, from seedlings a few inches in 
height to trees in full bearing. (4) No external conditions can 
insure safety. Trees in sheltered positions suffer in the same manner 
as those fully exposed, although in some instances a sheltered position 
appears to retard the progress of exhaustion. On the other hand, 
trees grown in sheltered positions are speedily exhausted when the 
shelter is removed. (5) If the demand upon the vital energies of an 
affected tree is reduced by removing a portion of the branches, the 
remaining branches usually exhibit an improved appearance, although 
of a temporary character. (6) If a tree be headed down when first 
seen to be affected, luxuriant and apparently healthy branches are 
speedily given off from the stump, but this also is only temporary ; the 
te signs of weakness are usually exhibited the following spring, if not 
before. 
This weakening of the vital energies of the plant has been mainly 
effected by growing peaches on their own roots, and is to be seen in 
all countries where such a course has been followed. This is notably 
the case with the old Maori peach-groves, where one generation of 
trees after another has grown up from seed; and the same may be 
said of the cultivated trees in the orchards and gardens of the settlers. 
All the peach-trees in the colony have been either raised from seed or 
have been worked on peach-stocks. , 
The first step in the work of renewal will be the selection of a 
suitable stock, and this we find in the mussel-plum, the stock in- 
variably adopted by English nurserymen, who have to carry on the 
cultivation of the peach under far more unfavourable climatic con- 
ditions than prevail with us. 
