142 PICTORIAL PRACTICAL CARNATION GROWING. 
Thrips. 
The small lively insects known as thrips, also as “thunder” and 
‘black’ flies,” belong to the section of the order Neuroptera named 
Thripidae, and are familiar to Carnation growers as very destructive 
to his plants, both outdoors and under glass. The thrips undergoes 
an incomplete metamorphosis, the larva being like the adult, with the 
exception of the absence of wings and certain peculiarities of colour. 
The adults are nearly always black, and have long, narrow, equal, 
veinless wings, fringed on each side with long hair, and laid horizon- 
tally along the back when at rest. They fly or “jump” about 
in large numbers, and attack the leaves and flowers of the plants, 
sucking out the juices, and often causing much loss. 
There are several species, but that usually attacking Carnations 
under glass is Heliothrips haemorrhoidalis; it is present in heated 
structures throughout the whole year. Outdoors the species that 
attacks the Carnations in summer is Thrips minutissima, which 
cripples both the foliage and flowers. The insect finds its way from 
the young growths, which it turns almost white by sucking out the 
juices, to the flower buds, and even sucks at the tender calyx, causing 
whitish marks, and as soon as the calyx segments open it enters the 
flower buds and feeds upon the developing petals. In hot seasons, if 
the plants are neglected, the thrips become so numerous in a partially 
expanded bloom that they may be shaken out in scores and are 
easily seen on a sheet of white paper, though not more than 7; inch in 
length. They completely ruin the expanding blooms. 
Drought or poverty is the cause of thrips infection. The proper 
way, therefore, to avoid attacks is toduly supply the plants in beds 
and borders with proper supplies of water and liquid nourishment, 
and syringe them daily when in the bud state, especially when the 
plants are grown on dry soils in hot positions. In case of attack, the 
plants may be dusted with tobacco powder when wet, or as this is 
somewhat unsightly the plants may be sprayed with a_ boiled 
decoction of White Hellebore, 1 oz. to 1 gallon of water. This is a 
certain remedy, but it must be applied before the thrips get into the 
flower buds. 
In the case of plants under glass, or those grown in pots that can 
be taken indoors, vaporisation with nicotine compound on two or 
three consecutive evenings (not when the sun shines) will destroy the 
pests. Many will leave the flowers, settle on the stages or floor, 
remain there until the smoke or vapour has cleared, and then return 
to the plants. It is well, therefore, to have the benches and floor 
wet, but there must not be any water on the foliage or flowers. 
Other Pests. 
The frog hopper, which covers itself with a white froth (“cuckoo 
spit”), should be crushed. 
Rabbits must be kept out by wiring. 
Slugs are reduced by applying lime water at night ; or they may 
be trapped with heaps of brewers’ grains. : E 
