876 
THE TROPICAL 
AGRICULTUEIST. [Dec. 1, 1899. 
bringing more oil iii contact with the insect, and 
also by its greater permanency.' Taking everything 
into consideration, neither kerosene, nor mixtures of 
the oil and water, can be recommended for general 
use — at any rate in the Tropics. 
Resin washes. — These are used extensively in Cali- 
fornia to remove scale insects from fruit trees. The 
formula (taken from Butletin, No. 9 of the U.S. 
Dep irtment of Ariculture) is a? follows-. — ' I he summer 
wash usually contains twenty pounds of resin, five 
pounds of crude caustic soda fseventy-eigbt per cent.), 
or three and a half pounds of the ninety-eight per 
cent., and two and a half pints of fish oil. The winter 
wash cantains thirty pounds of resin, nine pounds of 
crude soda, and four sindahalfpintsofoil. The ingred- 
ients are boiled ia about twenty gallons of water for two 
or three hours, hot water beii g occasionally added 
until fifty gallons of solution are made. This, for 
both formula, is diluted to one hundred gallons 
before application to trees. Greater efficiency is be- 
lieved to come from long boiling of the mixture, and 
it is preferably applied hot. It is used on deciduous 
trees for the black and San Jobe scales, and on citrus 
trees for the red and black scales ; but the dense 
foliage of the latter renders thorough spraying diffi- 
cult except for young trees, and fumigation is much 
preferred. An improperly made resin wash is also 
apt to spot the fruit of the orange." I have no 
personal experience of either this or the fuUowing 
insecticide. 
Lime Salt and Sul2)liur If ash. — This has been em- 
ployed against the San Jose scale in America. 
Though undoubtedly effective in some parts of the 
country, it appears to have completely failed in others. 
Mr. Marlatt writes : — ' Our experience with this wash 
in the East (Eastern States) had thrown doubt on 
its real efficiency as an insecticide, and it has been 
clearly demonstrated that under the climate condi- 
tions east of the AUeghanies it is almost valueless. 
In California, however, after a careful study of tlie 
facts in the field, I am compelled to admit that the 
demonstration of its usefulness against the SanJote 
scale is complete, and the benefit of its application 
to orchards is most manifest. In the vicinity rf 
Pomona, California, unsprayed orchards were badly 
infested with San Jose scale, while in adjoining 
sprayed orchards the scale was entirely killed, and 
the trees were rapidly recovering and showing vigor- 
ous and healthy new growth. Ia contiguous orchards 
also of the same kinds of trees, similarly treated 
so far as cultivation ia concerned, the trees which 
had been subjected to yearly spraying were at least 
one-third larger than untreated trees. This wash is 
of value also as a funj^icide, protecting stone fruits 
from leaf fungi, and is also a protection against 
birds, the Common California linnet doing great 
damage to buds in January and February. The wash 
is almost invariably made and applied by contractors, 
and costs about five cents per gallon applied to the 
trees. It is a winter application, being applied in 
January and February. 
'Along the coast region and in Northern California, 
where moisture conditions prevail, this wash is very 
much less successful, bearing out somewhat the ex- 
perienced of the East, and doubtless explained by 
the similarity of climate in the districsts mentioned 
with that of the Atlantic seaboard. 
' In making this wash the chief consideration seems 
to be prolonged boiling. The wash itself is prac- 
tically a sulphide of lime, with much free lime and 
salt carried with it. Prolonged boiling will result 
in taking up temporarily additional sulphur, and will 
perhaps add to its caustic properties if it is applied 
very hot; on cooling, however, it reverts to the 
simpler tri-or bi-sulphite of lime. The proportions 
of the ingredients and the method of combining 
them vary slightly in different sections. The follow- 
ing is the ordinary formula: Unalaked lime. 40 
pounds ; sulphur, 20 pounds; salt, 15 pounds. One- 
fourth of the lime is first slaked and boiled with 
sulphur in '20 galloHs of water for two or three 
hours ; the remainder of the lime ia slaked, and 
together with the salt, ia added to the hot mixtare, 
and the whole boiled for half an hour or an honr 
longer. Water is then added to malie 60 gallons of 
wash. This wash is applied practically every year, 
or as often as the San Jo£6 scale manifests itself 
in any numbers.' 
Carbolic Acid. — Crude carbolic, phenol, Jeyes' fluid, 
and similar compounds, all have insecticidal properties. 
Carbolic acid itself has been found inefficient ex- 
cept when applied in such strength as to seriously 
damage the plants. I find that phenol and Jayes' 
fluid (which appears to be much the same thing) 
are effective against Orthezia, ' mealy bugs,' and 
moot species of Lecanium. A mixture containing 1 
part of Jeyes' fluid to 20 of water, applied to a 
Thunbergia bush attacked by Orthezia, was fatal to 
more than 90 per cent, of the insects, but resulted 
in the death of the terminal buds of the plant. 
It had no bad effect upon the more mature leaves 
and shoots. The application did not, however, pre- 
Tent the subsequent hatching of the eggs in tho 
ovisacs of the dea 1 insects. Weaker solutions were 
proportionately le^s effective. 
In a ' Report on the Green Scale Bag, Lecanium- 
viride,' published in 1886, I have mentioned that 
phenol applied to the ground around the roots of 
the coffee tree appeared to cause the disappearance 
of the scale. But subsequent experiments have not 
corroborated this result, and I must suppose that 
the apparent benefit in the earlier experiment was 
due to some other cause. Single experiments are 
practically useless. Thsy are liable to be vitiated 
by adventitious circumstances. Until similar results 
have been obtained from repeated experiments, no 
confidence can be placed in any treatment. 
Tobacco Water. — ' Steep 5 lb. of refuse tobacco 
(stems, &a.) in 3 gallons of water for three hours. 
Strain the decoction and add sufficient water to 
make 7 gallons.' The mixture will kill soft-bodied 
species that are unprotected by a covering scale, 
such as Lecanium viride, Pulvinana 'pasidii, aud Dac- 
ti/lopius citri. It has little or no effect against the 
L iaspidmce. 
Lime Water. — In the early days of the 'green 
coffee bug' I used a very thin wash of quick lime 
aud water. The mixture is inconvenient or difficult 
to apply as a spray, as it quickly clogs the nozzles 
and valves of the machine. I applied it with large 
brushes to the affected coffee foliage, and it was 
certainly fatal to every insect with which it came 
in contact. The bugs turned from green to a bright 
orange colour within five minutes of the application. 
But many individuals necessarily escaped, and the 
benefit was only temporary. No damage to the 
trees was observed, but the lime had such' a caustic 
effect upon the hands and arms of the coolies e£o- 
ployed in the work that it had to be discontinued. 
Stnnvson's Mixtures. — I have recently had the op- 
portunity of experimenting with a mixture supplied 
by the Strawson Company for use against the Tea- 
mite, and have found it very effective against scale 
insects of all kinds. It is one of the few insecticides 
that I have found of real value against Orthezia. 
Applied as a spray in the strength of ]| lb. to 4 
gallons of water, it not only kills this insect, but 
prevents the hatching of the eggs also. This is ap- 
parently effected by the blocking of the aperture of 
the ovisac, and so preventing the emergence of the 
young insects. The mixture fas supplied^ is of a 
soapy nature, and it is the soap that is probably the 
active agent in the destruction of the scale iusecta. 
The ingredients are naturally kept secret by the 
manufactures, for which reason I am unable to re- 
commend its use as a spray for tea during the pluck- 
ing season, but for the removal of scale insects upon 
other trees it will be found of value, and I have 
frequently used it advantageously to clean the stems 
of Pruned tea. It is particularly effective also against 
the ants (Cremastogaster Dohrni) that give such 
trouble by building their nests in the tea bushes. 
These nests always enclose a colony of scale insects 
("usually Lecanium formicarii), and to prevent the re- 
currence of the ants it is most necessary to get rid 
of the bnga that attract them. For application to 
