14 
APPLE. 
AMERICAN BLIGHT (Schizoneura lanigera), 
Unhappily this insect is too generally distributed throughout the 
colony to need description. Its presence on an infected tree is at 
once indicated by cottony-looking tufts or patches, which, if neglected, 
increase in size, the cottony outgrowth often attaining a length of two 
or three inches. The aphides vary somewhat in colour, but most 
frequently are black or purplish-black, the young of a faint reddish 
tinge; the cottony outgrowth is produced from their abdomen ; but 
the process of development has not been fully made out. 
From eggs hatched in the spring wingless insects are produced, 
each of which becomes the mother of a colony, and may be termed the 
“ queen aphis”’; she is viviparous, and able to produce several genera- 
tions of insects without the intervention of the male. The young 
insects are also viviparous, and, as they are able to commence the 
work of reproduction when five days old, their rate of increase is 
enormous. It is no exaggeration to say that a single queen may have 
many billions of descendants even during her own short lifetime. 
The sexless insects thus produced resemble the queen, but are of 
smaller size and more oblong form; they are also of a brown or 
purplish-brown colour, while the queen is nearly black. Viviparous 
winged insects are occasionally produced, but they are certainly 
infrequent in the colony. On the approach of winter perfect-sexed 
insects are developed, which pair, and in a few days the female deposits 
her eggs in a crevice of the bark and dies. The eges remain dormant 
until the following spring, when new queens are developed. 
The sexed individuals have no mouth-apparatus, and are unable 
to take food, so that their existence is of brief duration. They are of 
smaller size than their viviparous parent. 
In the North Island there appears to be no absolute cessation 
of the process of viviparous reproduction. Wingless insects are 
certainly extruded during the winter months, although in reduced 
numbers. 
The woolly aphis is found in crevices of the bark, or at’ the forks 
of branches, at the base of suckers, or even in the axils of the leaves. 
In many cases the roots are attacked and large galls formed, which 
vary from one to four inches in diameter. 
The insect punctures the bark and pumps up the sap, which not 
only weakens the tree but causes an excessive flow of sap to the 
affected part, resulting in a diseased warty growth: the bark becomes 
cracked, and exposes the tissue beneath to further attack, while a new 
growth forms round the margin of the fissure, thus affording a larger 
amount of shelter to the insect, and more copious supplies of food to 
the ever-increasing colony, until at length stem and branches alike 
are thickly studded with warty excrescences, partially clothed with the 
white outgrowth so characteristic of American blight. 
Tt has been contended that the aphis attacking the root belongs 
to another species, which has been described as Schizoneura pyri. I 
