1 June, 1902.] QUEENSLAND AGRICULTURAL JOURNAL. 451 
The Orchard. 
QUEENSLAND AGRICULTURAL COLLEGE. 
The question is often asked, both in Europe, in the United States, and in 
the States of this Commonwealth, “Do Agricultural Colleges do any good ?” 
Usually the reply is in the affirmative. 
What is the raison d ’étre of Agricultural Colleges? They are certainly 
not intended to be merely farms and orchards worked for the direct pecuniary 
benefit of the State, kept up by the funds of the taxpayer, and entering into 
competition with the farmer and fruit-grower who has only his own capital and 
labour to depend upon. Yet this is precisely the view that unthinking people, 
and especially people with no knowledge of rural pursuits, adopt. They fail to 
understand that cai agricultural colleges are expensive to keep up, and return 
no direct profit to the State, yet they are invaluable institutions for the training: 
of young men in the various branches of rural economy. Already numbers of 
the students of the Queensland College have, after their three years’ course of 
study, obtained employment on farms, in creameries, butter factories, and 
- dairies. Numbers of others have taken up land for themselves and have become 
successful wheat and fruit growers, dairy farmers, &c. The instruction given 
at our college is bearing fruit in manifold ways beneficial to the State. 
As showing what kind of education, theoretical and practical, is given to our 
students, we have been asked to print a paper written by one of them, Mr. M. 
R. Fox, and read before the College Debating Club. We do so with pleasure, 
as the paper is intelligent, practical, and devoid of unintelligible language so 
common to writers on scientific subjects. It is entitled 
Sprayine anp THE Desrructrion or Prsrs. 
. Before commencing to speak on this subject I must express my regret at 
being unable to read this paper at our last meeting, and also that it will not 
be as long and instructive as I would wish, owing to my being unable to secure 
any books that afforded information that I might check my remarks by. 
However, I have done my best to prepare as instructive and reliable a paper 
as I can, and hope you will deal leniently with it in your criticisms. 
- Sprays are used mainly to contend with fungoid diseases and insect pests, 
and are therefore divided into two classes—‘ Fungicides” for fungus, and 
“Insecticides” for insect pests. Up to the present time no one spray has 
been invented that will act equally well on both these pests, and as they require 
different substances for their destruction it is not likely that there will be one. 
Insects differ greatly in their mode of attack, and therefore they will 
require different treatment. For example, take the “aphis” of the peach 
and the “Codlin moth” of the apple. The former causes mischief by suckin 
the juice from the plant; the other lays it eggs at the calyx of the fruit, rl 
the larva does the work of boring about inside. Scale insects and borers again 
must be treated differently to those that gnaw the leaves and outside of the 
lant. 
# To destroy insects that eat the outside of the leaf or bark, a fine spray or 
powder of some poisonous substance is used. Generally these insects are more 
easily and cheaply got rid of than any other kind. The commonest of the 
poisons used against these pests are Paris green and London purple—in fact, 
these two are the only ones in general use. These compounds contain arsenic, 
in the Paris green as aceto-arsenite of copper, and in London purple as. 
arsenite of lime. The Paris green is more to be relied upon as haying sufficient 
strength ; the amount of arsenic in the purple often varying considerably. 
The latter is more soluble in water than the Paris green. One ounce of the 
powder to 10 gallons of water is the standard strength, although on some 
varieties of apples and other delicate foliaged trees it is advisable to weaken 
the mixture to 1 oz. to 12 gallons. If used stronger, the Paris green especially, 
