April 1, 1899.] THE TEOPICAL 
AGRICULTURIST. 
675 
and the least injarions to the plants. The gas 
treatment however, thoufih really very simple, requires 
considerable care ia application and is subject to 
certain dangers. It cannot therefore be recommended 
for general use without previous demonstration by 
a trained operator. 
Spraying is the next best measure. But however 
throughly this work may be done, a certain pro- 
portion of the insects is bound to escape, and the 
Erocess must be repeated at intervals until the pest 
as finally disappeared. I hare found that mixtures 
of which soap is the principal component are more 
efficacious against Orthezia than any other form of 
insecticide. Besides killing the insect, the soapy 
matter blocks the aperture of the ovisac, and so 
prevents the emergence of the young larvae. Ke- 
rosine-soap-emulsiou is a useful and inexpensive 
mixture, but requires careful preparation. The 
formula is : — 
Kerosine ... ... 2 gallons 
Common Soap ... ... i lb. 
Water ... ... 1 gallon 
Dissolve the soap in water heated to boiling. Add 
the kerosine to the hot mixture, and churn till it 
forms a thick cream on cooling. The churning is 
the most important part of the process. If this 
ia not done throughly, the oil separates out on 
cooling, and will not then mix with water. A pro- 
perly compounded emulsion may be subsequently 
diluted to any extent. The churning may be effected 
either by stirring vigorously with a bunch of twigs 
or the liquid ma}' be repeatedly drawn up and ex- 
pelled through a garden syringe. To test the mixture, 
put a drop on to a piece of glass. If it adheres 
without separating into oil globules, the process is 
complete. For application, dilute with nine or ten 
times the bulk of water. Kerosine emulsion should 
not be applied during sunshine, or serious injury to 
the plants may result. 
Strawson's ''iled Spider Insecticide" and Mc- 
Dougall's "Insecticide Wash" are very convenient 
forms of snap mixtures, and are both very effective 
against Orthezia in the proportion of I5 lb. of the 
mixture to 4 gallons of water. 
The insects will remain attached to the plant for 
a long time (sometimes two or three weeks) after 
they are dead. An examination with a hand lens is 
necessary to determine whether the application hfis 
been successful or not. If the legs remain rigid and 
do not move when the insect ia disturbed, it may be 
presumed to be dead. 
After spraying it will be advisable — where possible — 
to prune the bush and burn the pruuings. 
Where the pest has become widely distributed, — 
as on Liantana in waste land, — any treatment of the 
above nature will be quite impracticable. In such a 
case all we can do is to endeavour to keep it in 
check by periodically cutting back and burning the 
Lantana and other weeds that lodge the insect. In 
districts where Orthezia is prevalent all boundaries 
should be kept carefully cleared back. If Lantana 
is allowed to encroach upon the tea, the latter is 
bound to become affected sooner or later. 
NATUR.\L ENEMIES. 
Natural enemies may possibly exist in the native 
country of Orlliezia insiynis. But, so far, the career 
of the pest in Ceylon has been unchecked by any 
such causes. Birds do not feed upon it, and I have 
not found a single insect parasite — external or in- 
ternal — preying upon it. I have tried to induce 
various species o£ lady birds to eat this insect, but 
they have one and all absolutely refused — prefering 
to die of starvation. 
A writer in tho ''Kew Bulletin" (June-July, 
1895) quotes from the " Timehri " (a Demerara 
Journal) in which Mr. II. Ward gives some account 
of the habits of the Ortliruia (in Demerara.')' 
Ho says : " Altliongli common, it is not nearly so 
destrnctivo or troublcnomo as many of its allies. 
In the young stale it is very abundant ; after it 
becomes fully daveloped it is more easily preyed 
upon by its natural enemies, which play an im- 
portant part in limiting its ravages. In this res- 
pect no insects are more assiduous than the grubs 
of the different species of CoecincUa (lady. birds), 
Si/rphus, the various Ilemerohidm, of which tlie different 
species of diri/sopa act a chief part." It would be 
interesting to know if Mr. Ward is speaking of his 
personal observation of the natural enemies of the 
Orthezia, or whether he is alluding in general terms 
to the acknowledged work of such natural enemies. 
MODE OF DISTRIBUTION. 
The young larvai of all scale-insect are very easily 
transported from one place to another. They are 
minute and active, and can exist for several days 
without food. They may crawl on to the feet of 
birds, or even on to larger insects that may be 
resting on the bug-infested plant and may be con- 
veyed in this manner to a considerable distance before 
being dislodged. They may be brushed off the 
plant and carried away on the clothing of passers by. 
The rough cumblies used by Tamil coolies aie 
particularly liable to carry the infection. Wandering 
cattle are also unconscious distributors of the pest. 
The young insects are so light that they may be 
transported by wind. The conspicnous way in which 
the pest is spreading along the sides of the railway track 
points to the supposition that they are carried along 
by the draught of passing trains. Eunning water 
is auother fertile source of distribution. An infested 
plant growing on the banks of a str^m or river 
is sure to shed some of the iesect in the water. 
Individuals may be floated down for miles 'before 
effecting a landing. 
The interchange cf garden plants is also a great 
source of danger. It was in this way that the pest 
obtained a footing in Ceylon. 
BIBLIOGBAPHY. 
References to Orthezia insie/nis may be found in the 
following papers and publications:— 
(1) Journal of the Quekett Microscopical Club Ser 
20 (Dec. 1887), p. 109, et see, ; 2 
plates ' Jvotes on a Species of Orthezia found in 
Kew Gardens," by Edward T. Browne 
(2) Entomologists' Monthly Magazine (Jan , 1888) 
p. 169, with several figures (A Description of the 
a species, by Mr. J. W Douglas). 
(b) Thiity-Second Annual Report of the Massach- 
usetts Agncultural College, for l«9.l. '.a New Green- 
house Pest, by C. P, Lounsbury. 
(In the three papers quoted above, the male of 
a epecies oi Daeti/lopius is erroneously described and 
figured as that ot O. msie/nis.) 
(4) Annual Report on 'the Royal Botanic Gardens 
Peradeniya, for 1893, by Dr. H. Trimen. (Mendon 
of injury by the pest.) v^icmion 
(.)) Indian Museum Notes, Vol. riL, No Iri .'l^iqji 
tn^F R S ""''"'^ '^""^ G. B. Bu'l 
fr ^-^ f JO- nacrea IS here ^synonym of O-in^i-jnis). 
(bi Tropical Agriculturist (Jan., 1895 1, p 487. i 
plate. "An Important Insect Eenev," hu '\i,-'i? 
E. Gi-een, P.E.S. (Giving a description of^he pesi 
and Its ravages in Ceylon.) [Afterwards reprinted 
in pamphlet form.l 
( 7) Timehii Vol. Ill,, New Series a889), p 308 
with fignres. (Reference to the occurrence nf tV, ' 
insect at Kew, by Mr. S. J. Mclntvre ) " 
(8) Timehri, Vol. IV. (18901 n rA 
oi\L Habits 'of the O./S ' Mf-" I ^Vard?' 
,9) Kew Bulletin (June-July, 1895 p ijo'''* 1 
ference to the pest at Kew and elsewliere » ' 
5 
^]^X ?n'°'"?'''8i?'f^°°'h'y Magazine (June 1895) 
(11) Annals and Magazine of Natural Historv Vnl 
XVI. (July, 1895). ."On some CoccidL by 
Mr. C. A. Barber in the Island of Anti'^ia W I - 
by Professor T.D.A. Cockerel] ^^""o""', \\ . I., 
(12) Bulletin of the United States Department 
ot Agriculture, Division of Entomology. Technical 
Series No. 1 (IH'M), pp. lo, n ■• (J,^ L 
