<A MONTHLY. 
XX. 
COLOMBO, DECEMBER 1st, 1900. 
No. 6. 
SOME CATERPILLAR PESTS OP 
THE TEA PLANT. 
OWARDS the end of last year 
(1899) there were numerous 
complaints, more particularly 
from the Dikoya district, of 
serious and repeated injury by 
the small leaf-twisting cater- 
pillar known as the Tea Tor" 
trix. It was suggested, by the 
then Chairman of the Planters' Association, that a 
circular on the subject would be of assistance to 
he planters. Having insuificient data for the pur- 
pose, I asked for further particulars and dates of 
recent visitations of the pest, together with 
memoranda of the total monthly rainfall in the 
districts concerned. In response to my request a circu- 
lar letter was sent to the various branches of the 
Planters' Association asking for the required informa- 
tion. In due course a large packet of correspondence, 
the result of this circular letter, was submitted to me 
by the Secretary of the Planters' Association. It ap- 
pears, however, that in the letter in question the pest 
was referred to as " The CaterpiPar Pest ;" and it was 
at once evident, from the nature of the replies, that 
each observer had applied the term to the particular 
pest that had been the most notorious in his district ; 
and that the correspondence referred to some five or 
six distinct species of caterpillar. Under these circum- 
stances I have thought it advisable to draw up a cir- 
cular on Tea Caterpillars in general, giving detailed 
particulars of those species that rank as really serious 
pests. This plan will be quite convenient, aa the 
general treatment suggested will be practically the 
same for all the different species. 
As a rule, caterpillar pests are of less real impor- 
tance, and much more readily controlled, than are 
m»ny less conspicuous plagues, but there are some not- 
able exceptions. 
It will be well to briefly outline the life-history of 
insects of the Order Ltpidoptera (Butterflies and Moths), 
of which the caterpillar,'is but one of the earlier stages, 
The series consists of (I )Ovnm, or Egg ; (2) Larva, or 
Caterpillar; (3) Pupa, or Chrysalis (often enclosed in 
a cocoon) ; and (4) Imago, the Butterfly or Moth. This 
constitutes the single generation. A thorough know- 
ledge of all these different stages is of great importance 
in the study of any injurious caterpillar. Such know- 
ledge enables us to determine which may be the moat 
vulnerable stage in the life of our enemy, 
The destructive time is in all cases the caterpillar 
period, and to this stage, therefore, the chief attention 
must be paid. 
With most of our caterpillar plagues in Ceylon a dt- 
finite rise and fall is noticeable, commencing with a 
small brood, limited very possibly to three or four te» 
bushes only. Unfortunately this initial brood is almost 
invariably over-looked. Prompt measures at this time 
would prevent all further trouble. But these pioneer 
caterpillars are allowed to go through their transforma- 
tions and eventually emerge as moths capable of repro- 
ducing their kind perhaps a hundred fold. They distri- 
bute themselves throughout the surrounding tea, and 
pregnant individuuls may be carried to distant quarters 
of the estate by the wind. They deposit their burden 
of eggs and die. In due course — varjing according to 
the individual species from three or four weeks to as 
many months — a second and larger brood appears, verj 
probably starting from several distinct centres. Even 
this more extensive brood may possibly not attract very 
much attention. The coolies observe a number of 
caterpillars about, but do not consider it their business 
to bring it to the notice of the superintendent. The 
consequence of this inattention is that a few weeks later 
the caterpillars appear in such countless numbers and 
effect such serious damage that it is impossible to over- 
look their presence. The superintendent becomes al- 
armed, collects and destroys as many of the caterpillars 
as ho can, and probably prunes down the affected field 
