July i, 1897.] 
THE TROPICAL AGRICULTURIS I . 
5 
the syringing is given with such force as to knock 
them from the plants, the insects are but little 
hurt. It is for this reason that soft-soap is so 
largely used, especially by hop-growers, for the 
washes : it is sticky, and thus adheres, in some de- 
gree, to the aphides, ; also it may be made the 
vehicle of any other application with which it may 
be desired to poison the aphides ; and, thirdly, it 
is a good fertiliser, which, as we have observed, is 
important in aphis attack. 
The great thing, however, that we need to know 
in order to check aphis attack, is where and how 
each kiud spends the winter. Meanwhile, our best 
hope as to prevention lies in allowing as few 
shelters as possible on trees, or in neglected bark 
(in fruit or tree attack), or at the roots of wild 
grasses round fields, for possible shelter of grain 
aphis, and, genenerally, being alive to the necessity 
of not letting everything drift without thought of 
the reason how, or why, things happen ; and, for 
remedy, in use of washes which are known to be 
suitable for the purpose in hand. 
The wooly aphis, or American blight, is chiefly 
to be found in neglected orchards. The aphides 
shelter themselves for the most part in crevices of the 
bark, or where a bough has been injured, or under 
young bark healing over wounds ; but they may 
be found on the young shoots, and the leaves, and 
are distinguishable by the white cottony material 
which surrounds them. I have flso found this 
kind of attack on the rootlets. The piercing of 
the aphis-sucker causes the growth just below the 
bark to become swollen and pulny ; then the cells 
divide, and the bark above splits, and thus openings 
are formed, which give the aphides new hiding 
holes ; and the diseased growth from their punc- 
tures is continued, until large tumour-like masses 
are formed, and the trees are very seriously in- 
jured. 
The best method of check ng attack is to keep 
the bark of the apple trees in such a healthy state 
— by means of proper pruning, the clearing away of 
injured branches, and useless and cracked bark 
(and other measures) — that there may be as few 
cracks and crannies, and half-healed spots, as 
possible, consequently, as little as possible of the 
shelter in which this aphis delights. Also, when 
the white wool in any nook or on any soft shoot 
in summer time, shows the presence of the pest, 
the shoots should be at once cut off, aird some 
remedy should be well brushed or rubbed into 
infested nooks. 
The number of difierent kinds of applications 
advised are almost beyond counting, though the 
principle throughout is one. But anything will be 
ef use which will stifle or poison the aphides, 
without hurting the bark of the tree ; and pro- 
bably common soft-soap, or soft-soap with a little 
sulphur dissolved in it, or paraffin or tobacco-juice 
added to it, and well rubbed or washed in, so that 
it may be sure to reach the pests in their sheltering 
nooks, will answer as well, or better, than most of 
the many suggested applications. Some of the 
applications said to succeed should he applied (if 
at all) with great caution, or they may do more 
harm than good by soaking into the bark. Tar is 
especially to be suspected, for it is apt to melt in 
the heat of the sun ; and turpentine, resin, and 
fish-oil, mixed and put on warm, and, in fact, any- 
thing that will thus choke the bark, is an unsafe 
application. 
For attack below ground, the best treatment 
seems to be the clearing away of infested roots and 
soil round them, and drenching the spot well with 
soft-soap washings or drainings from stables. 
The fifth tribe of aphides (the lihijzobiinte) feed 
mostly on grass-roots, and are wingless ; 
should they be found troublesome, the use of the 
cultivator, 'plenty of gaslime, and similar measures, 
would probably clear them cut 
In is exceedingly difficult to give any clear 
view of aphis life, or means of prevention, for few 
are known, excepting in cas' s where the plants are 
under cover, and where, t.i fsre, lumigrtion can 
be brought to bear. But the principle throughout 
appears to be this : — Check attack by diniinisbing 
lurking-places, and also by pruning off and destroy- 
ing infested shoots and parts of plants, or infested 
leaves (as with cabbage), as much as you can : and 
where you can bring washes to bear, use soft-soap 
as a foundation; but where tho application may be 
run into the ground, and thus remain round the 
insects, ammoniacal water, or drainings from 
stables, lime-water, or other drenchings poisonous 
to insect-life, and that will not hurt the plant 
have proved useful. ’ 
The “scale insects’’ are tho third section of the 
Ilomoptera. 'Ihese insects do great harm by 
drawing away the sap by moans of their sunkers^ 
There are many kinds, differing in various points of 
structure, as well as form; but in the case of 
the apple mussel scale which is sometimes very 
hurtful in orchards, this shell-like husk, which is 
in shape like a minute mussel-shell, adheres firmly 
to the bark during winter; and under it, but not 
attached to it, there lies the dead body of the 
female scale, and fifty or more eggs. In spring 
these hatch, and from them come small white flat 
insects, furnished with eyes, horns, .six leo-s and a 
sucker. These are very active at first but pre- 
sently each scale larva runs its sucker into some 
spot it can pierce, begins to feed, and ceases to 
move. A secretion of waxy material takes place 
on its back, beneath which the scale forms; and 
after various moults, and additions by secretion to 
the size of the scale, the change of the insect under 
it takes place to the perfect state. This, in the 
female, is to a shape like that of a globular flat- 
tened maggot, greenish in colour, without joint 
imbs, which lays eggs and dies. The males (I 
believe, in the present case, first observed not loog 
ago by Prof. Edey) have one pair of whitish wings 
and mr proboscis. ” ’ 
The best method of getting rid of these scales 
IS to prune off infested boughs, where this can be 
done. Where it cannot, rubbing off the scales by 
means of cloths or brushes, after moistening the 
bark witli water, or scraping them away with a 
knife, gets rid of many; and, generally, the same 
kind of remedies are useful as are applied for 
American blight, such as soft-soap, with some 
mixture of paraffin, kerosine, or other addition 
which may stifle the scale insects which have been 
disturbed, and make the bark unsuitable for 
attack. 
ihe order of plant bugs includes both plant and 
water insects, which may be known by a kind o^ 
leathery patch at the base of the front wing-* 
■ dis-similar” from the rest of the substanc,' ! 
whence the order takes its name of lleterontcra or 
dissimilar-winged. ’’ The long-legged insects 
known as water measures, which we see skimming 
about on the surface of ponds, and the water boat- 
men, which by the help of their long oar-like front 
legs sweep through the water like insect skiffs 
are commm examples of the water irequenters of 
this division. 
The plant bugs sometimes do harm by sucking 
lha ^ juices of plants, especially by LyaiiM 
solam, which attacks potatoes ; but they are 
so far as I am aware, rarely injurious in this 
country to any serious extent. Some kinds ot a 
longer narrower shape, are to be found on wheat 
ana birrley. The wheat bug (.lA'i-is tiiticij has also 
otteu been found on grass in marshes ; the hurlev 
bug (.1/. dolabralusj ,s exceedingly’ common ^ 
barley, and on flowers ot grass near. 
Some of these various ou‘-:f-door bugs probably 
do good, by means of their carnivorous habits • 
and with regard to the wingless kind which to 
our misfjnnue, occasionally teaches us that feeding 
on animal juices, by means of a sucker, is a charac° 
teristic of this order, I think we need not enter on 
its preventicn here. 
The remaining oider is that of the thrips T/w 
sanop/era. These are very small insects, ’which 
sometimes do much harm to corn. They are 
