140 PICTORIAL PRACTICAL CARNATION GROWING. 
in spring, the soil will usually be freed from the pest, and probably 
also from Carnation fly pupae. 
The potting soil should be thoroughly examined before use. The 
wireworms are easily detected if it is turned over. Always remember 
that the materials for forming compost cannot be too thoroughly 
rotted, sweet, and wholesome. 
Aphides or Green Fly. 
The green fly that infests Carnations bears a close resemblance 
to, if it is not identical with, the corn aphis, dolphin, or plantlouse 
(Aphis or Siphonophora granaria). ‘The insects are of small size, 
green, very soft, and easily crushed with the fingers. They cluster 
on the ends of the young growths in great numbers, causing 
considerable injury by drawing away the sap, and thus not only 
exhausting the strength of the plant, but also effecting much damage 
to the tissues by means of the many minute punctures. In this 
way, together with the exudations and excretions, known as “ honey- 
. dew,” deposited on the foliage and clogging the respiratory organs, 
the whole plant is rendered unhealthy. Even slight attacks cripple 
the growth and give rise to the condition known as “stigmanose,” 
sometimes, especially under moist conditions of atmosphere and 
sluggish root action, resulting in decay and accompanying bacteria. 
Stigmanose is declared by some mycologists to be identical with 
the trouble known as “ bacteriosis of Carnations,” but this occurs in 
the British Islands apart from previous infestation by aphides. 
The aphis is said to deposit eggs on the leaves of the Carnations 
in late summer or autumn, and these are hatched with the warmth 
of spring, but the aphides are often found on Carnations in late 
summer and autumn, especially on the Trees, and unless destroyed 
they increase with marvellous rapidity, viviparously. The grower 
must keep a sharp lookout, and whenever an aphis is seen promptly 
take steps to kill it. 
Under glass the aphides are readily destroyed by vaporisation: | 
with nicotine compound, operating on two or three consecutive calm 
evenings and having the grass dry. A solution of quassia extract 
and other insecticides is also fatal to the aphides, if the plants are 
dipped into it. 
ANIMAL ENEMIES. FIG. 67 (NEXT. PAGE).—THRIPS. 
P, a plant which has not developed its flower buds properly on account of the 
attacks of thrips: i, grass with white marks on the leaves due to the 
punctures of insects, and black dots due to excrement matter, the 
growth is weakly and stunted; 7, buds that have been entered by insects 
as soon as the calyx parted at the apex, and much damage done to the 
unfolding petals, which have been prevented from developing further 
k, flowers that have at first a whitened, streaky appearance in the 
petals, afterwards turning brown and dying without expanding pro- 
perly, due to the attack of thrips. 
Q, thrips (Heliothrips haemorrhoidalis): 7, larva ; m, perfect insect. 
