MONTHLY. Po 
XX. 
COLOMBO, JANUARY 1st, 1901. 
No. 7. 
SOME CATERPILLAR PESTS OP THE 
TEA PLANT.* 
{Concluded fiompaye ST J:.) 
0. 5. — The " Moeowak koeale 
Nettle-grub." Thosea recta, 
Hampson. 
The eggs of this species have 
not yet been observed, but they 
are probably laid upon the 
surface of the leaves. 
Caterpillar : lozenge-shaped, 
slug-like, of an applegreen or yellowish-green colour, 
often with a series of irregular red patches on 
the back. Stinging spines arranged on small tuber, 
oles in b marginal and two dorsal series. Head 
concealed on the under surface. The insect has no 
legs, but progresses in a slug like fashion. The fully 
grown caterpillar measures from| to J inch in length. 
Coccon : dark brown, egg-shaped, compact, and 
smooth, attached either to the under surface of a tea 
leaf or in the angles of the twigs and stems. When 
the pest is at its height, the cocoons may be found 
in clusters on the twigs, the leaves ol the trees having 
been completely devoured. Specimens kept in capti- 
vity remained as cocoons for from 17 to 21 days. 
Moth ; grayish brown, with a rather furry body. The 
female has a blackish spot in the centre of the fore 
wing and two faint lines, one near the base and 
.he other near the tip. The basalline stops short of 
the front or costal edge of the wing. The male 
has a darker patch at the base of the wing bounded 
by a short white streak which (as in the female) 
does not reach the costal edge. The male moth has 
an expanse of f inch. The female is rather larger 
measuring slightly more than an inch across the ex- 
panded wings. The male may also be distinguished 
by the stouter (feathered) antennas, the corresponding 
parts of the female being thread-like. (Excellent 
figures of the caterpillar, cocoon, and moth appeared 
in "The Indian Museum Notes," Vol. IV., No. 2.) 
*Eoi/al Botanic Gardens' Circular, No, 19. 
I have been acquainted with the present species 
as a tea pest, for about eight years. A corresponu« 
ent, writing in the Ceijhn Observer of July 27, sayg 
that he can remember a severe attack as far back a3 
1885. I first received specimens from the Ambaga* 
muwa district, where large acreages of tea were 
defoliated. I next heard of it from Balaugodai 
The pest has probably asserted itself repeatedly in 
different districts, but the outbreak in Morowak korale 
seems to have caused a quite unprecedented scare. 
The superintendent of the estate on which it made 
its first appearance in that district has kindly sup« 
plied me with the following particulars : — 
" I first noticed it on July 15 ; it was seen on about 
half an acre of tea. After two days it had spread over 
about 3 acres, and then at the rate of about five acres a 
day over 25 acres of tea. [This rapid extension of 
the affected area could not have been caused by any 
actual migration of the army of caterpillars, which 
are sluggish and travel very slowly. It is doubtful 
even if they wander far from the bush upon which 
they were born. It probably arose from successive 
batches of eggs hatching out on consecutive days, de« 
posited by months which had dispersed from the centre 
of infection, where a smaller previous brood had under« 
gone its transformations unnoticed. — E.B.G.] The 
damage done was not of a permanent nature; but 
the caterpillars eat out almost every vestige of green 
leaf, and the whole 25 acres were stripped almost 
bare. When I found I could not prune quick enough 
to overtake its spread, I pruned broad belts round 
the area attacked, burning the prunings and sweep- 
ing the ground. I found the insects seemed unable to 
cross these belts, and as I pruned out all the tea in- 
side it died fast, exposure to the sun and want of 
sustenance apparently combining to kill it. 
" In about five weeks from its first appearance 
it had disappeared nearly entirely, although I found 
a few insects here and there in other parts of the 
estate. When, however, the young flush grew (about 
