THE PRICKLY PEAR PEST. 
by many varied means in their neighbourhood, as most of these segments will 
‘eventually take root and grow, and to the distribution around of the fruits. 
It can be quite understood how rapidly a lightly infested area becomes heavily 
infested, and the heavily infested almost ineradicably so. 
Let us now consider the question of eradicating prickly pear from infested 
areas. It is not proposed to go into this aspect fully. The means by which it 
can be eradicated will merely be briefly indicated. At the present time these 
methods may be placed under three headings—mechanical eradication; eradica- 
tion by chemical methods; and eradication by biological methods. 
Mechanical methods employed comprise cutting out or dragging out, followed 
by stacking and burning, and crushing by means of heavy logs or rollers. Jarious 
suggestions have been made which comprise in principle one or other of these 
methods. In this connexion may be mentioned the possibility of destruction by 
fire blasts, the heat employed causing rupture of the epidermis by the steam 
generated in the juicy parts of the leaf, besides scorching the dormant buds. 
The chemical methods of destruction on a large and practical scale so far 
consist in spraying with preparations containing arsenic, the segment being 
frequently injured by the application at the Same time of some caustic or 
escarotic such as sulphurie or hydrochloric acids or caustic soda, Destruction 
by means of gaseous fumes has, of course, been thought of, but no entirely 
satisfactory practical method has as yet evolved. 
The biological methods of contro] are represented at present by the use of 
a cochineal insect, which hus been found successful as regards one species of 
Opuntia, but, unfortunately, not against the most widespread species of the 
pest here. There is also the possibility that some fungoid or bacterial disease 
may be discovered which may be destructive to prickly pear. 
Here it may be mentioned that in all the methods hitherto tried for the 
eradication of prickly pear expense is heavy, and particular care is essential. 
Frequently the cost of eradication approximates to the value of the land. to be 
cleared. In many parts no attempt at getting rid of prickly pear has been 
made because the cost of eradication would be much greater than the value of 
the land reclaimed. It may be further added that great hopes cannot be held 
out that scientific endeavour, even by the ablest and most experienced of men, 
will discover an easy and rapid method of prickly pear destruction. There is a 
popular idea that there is a remedy for every evil under the sun. Those who 
have had experience of the control of pests and of disease know that such is 
by no means the case. It is true that there are not a few diseases and pests 
which can, apparently by accidental and fortuitous circumstance, be easily and 
cheaply controlled. In the great majority of cases, however, the control requires 
continued and unremitting toil, constant care, and outstanding common sense. 
The present position of the prickly pear problem will be seen from the above 
remarks to boil itself down to this: That there are great areas of prickly pear 
in two of our States which are yearly extending and becoming more aggressive, 
and that no means haye yet been discovered, or are likely to be found out in 
the immediate future, by which the areas at present infested can be cleared of 
prickly pear at a trifling cost. Wat, then, should be done under these circum- 
stances? It is obviously absolutely imperative to arrest the further progress 
and to beat back the prickly pear as rapidly and as quickly as possible. 
The following may be suggested as a basis for fuller discussion :— 
I. Assessment of the Distribution of Prickly Pear—Though to a considerable 
extent this is known, and data have been compiled from which the distribution 
of severely infested and clean country can be ascertained, it is very necessary 
uty) 
