JUNE 2, 189a] THE TROPICAL AGRICULTURIST. 
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PYRETHRUM (INSECT POWDER PLANT)_ 
The following compilation of particulars respecting 
Pyrethrum, the Insect-powder plant, will probably be 
interesting to those who know the value of petites 
cultures in piling up little profits. 
During the long series of desultory compaigns kept 
up by the Russian Government in the Caucasus, and 
resulting in the annexation of the country, the mili- 
tary cantonments simply swarmed with fleas. Like 
Pharaoh's frogs, these insects were everywhere, but 
were not as easily kept at bay. The floors of some 
of th e tents seemed to be alive with them, and the 
men were at their wits' end to get rid of the pests. 
They so effectually banished sleep, tbat whole com- 
panies would prefer to lie in the open and take their 
chance of weather; rather than share the tents with 
the fleas. 
Some of the Tcherkess prisoners, who knew the 
ways of the country better than their invaders, at 
last let out the secret of a plant whose smell was 
fatal to the lively flea; this was the Pyrethrum 
roseum. It did not appear to be in commerce, but 
was gathered up the mountain slopes at an altitude 
of 6,000 to 8,000 ft., whenever wanted, hung up to 
dry, and rubbed to powder between the hands. How- 
ever, before long, the collection of plants became a 
regular occupation among the shepherds, and a Ru«so- 
Armenian merchant named Yumtikoff bought all that 
was brought m, and manufactured the powder. 
From that small beginning arose a very consider- 
abe industry, the export tax upon which is a valuable 
item in the revenue of the province. 
It is not quite clear whether the success of P. 
roseum as an insecticle induced trials on other allied 
species, or whether the mountaineers of Dalmatia 
had already knowledge of the properties of a similar 
plant. But ere long Pyrethrum cinerarise folium was 
largely cultivated in the Littorale, and so anxious 
were the growers to keep the monopoly in their own 
hands, that all the seed sent out for sale to agents 
of other countries was carefully baked to prevent its 
gei'mination. In 1856, M. C. Willemot commenced the 
cultivation of Caucasian Pyrethrum on a large scale 
in France. His plants were examined by Duchartre, 
and, not being recognised as a slight variety of P. 
roseum, we' e called by him P. Willemotii Duch. This 
accounts for the two synonyms in vogue. 
For ourselves, it will be handiest to call the two 
species Caucasian and Dalmatian Pyrethrum respec- 
tively. Willemot recommends a somewhat open, dry 
soil, well-drained, and not too clayey in character, 
the plant being yerv ready to die when germinating 
in too much humidity, and easily killed when mature 
by water-logging the nursery-bed with careless irri- 
gation. The seed is best mixed with light sandy soil, 
sown on the surface of a well-prepared bed, and 
covered with a thin stratum of sandy mould. A 
light rolling after sowing is beneficial. The bed must 
not be allowed to dry out to the shallow depth of 
the seed. In about thirty days the young plants 
make their appearance, and as soon aa large enough 
to be handled, are transplanted 6 inches apart 
on a well-prepared bed. Three months subse- 
quently they are re- transplanted at double the 
former distance. The plants bloom in the spring of 
thuir second year. Thus far for the French practice. 
Here the greater heat of our climate, and a little 
careful management, may ensure flowering the first 
season. The best rule will be to treat the plant 
in about the same way as we are accustomed to treat 
Asters, Zinnias, and the like. 
In California the cultivation of the Dalmatian 
plant is carried on by a sattler from Dalmatia much 
in the same way as Mr. Willemot has directed. A 
fine, loose, open soil with a little old manure, form 
the nursery bed. The seed is mixed with sand, sown 
on the surface, and raked in to not more than half- 
an-inch in depth. Too much water will destroy the 
seed. Weeding aud transplanting in damp weather, 
when about a month old, concludes his directions. 
Of the two species, P. roseum is by far the more 
showy. Its flower is not at all unlike a rather poor 
103 
Aster, the rays varying from pinkish-white to deep 
blood-red. The leaf is cut like a Fern. P. cinerarias- 
folium is white-flowered, and has a considerable re= 
semblance to the Lasiospermum, or Oape white 
Camomile-weed, which covers outspans and roadsides, 
having a yellow disk and brilliant white rays, the 
underside of which is discoloured to a dull grey. The 
leaves are also Fern-like, but more coarsely divided 
than in the P. roseum. 
In the manufacture of the powder the flower-heads 
must be gathered in fine weather, immediately on their 
opening, as that is the period when the essential-ott, 
on which its insecticide virtue depends, is most plenti* 
ful. They are then dried in the shade, where a 
draught of air can be secured. Exposure to the sun, 
to moisture, or to artificial heat, deteriorates the pro- 
duoe extremely. When quite dry they may be ground 
at once, or preserved in tin canisters till the whole 
harvest is ready for manipulation. The plants them- 
selves are also cut to within 4 inches from the ground, 
and aftrr drying are ground up. Of this inferior pro- 
duce, one-third part by weight is added to the powder 
of the blossoms. There is no doubt that the Colonial 
snuff manufacturers could grind a better and more 
saleable article than could be prepared by any foreign 
applianoes. Of course, a coffee-mill, finely set, will 
somehow grind the material, but as the effect of the 
powder depends to a certain extent on its degree of 
fineness, it would be a pity to lose the advantage to 
be got by the special work of the snuff-mill and 
graduated sieves. 
It is not to be expected that Pyrethrum will be of 
any great use as an insecticide in agricultural opera- 
tions. Mr. Willmot, zealous to promote the new 
industry, prorosed to protect wheat and maize from 
weevil by mixing ten ounces of bis powder with ten 
bushels of grain. The effect would be scarcely ap- 
preciable. With bisulphide of carbon readily applied 
and certain in aotion, there is little reason to try 
Pyrethrum. 
It has been tried in the United States to destroy 
insects in gardens in various ways, e.g., in form of 
dry powder puffed over the plants, iu a mixture with 
water, and in fumigation. In all cases there is so 
much loss of the volatile oil by free contact with the 
atmosphere that its use can scarcely be said to be 
economical on any but a very small scale. Roses and 
Cinerarias may be cleared of aohis or green-fly by its 
means, but even in these cases the plan is amateurish, 
and prpsents no advantages over the old methods 
with tobacco water and tobacco fumigation. Domestis 
use as a safeguard against the lively flea is probably 
the proper outlet for the sale of Pyrethrum. — P. Mac- 
Owan, F.L.S., Cape Town Botanic Gc*rden.— Gardeners' 
Chronicle. 
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ARABIAN COFFEE, 
There is nowadays no question that Coffee arabica 
is of African origin. Its natural habitat seem to be 
the country of Gallas and Harrar. The plant was in- 
troduced into Yemen at the date of the Abyssinian 
oonquest, and the downfall of the Himyarite Empire, 
about a century before the era of the Hegira. The 
culture of Coffee rapidly spread in all the western 
parts of Arabia Felix — that is to say, in the regions 
subject to tropical rains. 
The system of cultivation has not altered for cen- 
turies, and the plantations of Coffee-shrubs on hori- 
zontal terraces on the mountain sides are to-day still 
like those of which Niebuhr wrote, more than a century 
. ago. The natural slope of the ground is sometimes 
very steep, consequently the walls of rough stones 
which sustain the terraces are built up to a height of 
from 20 to 26 feet, which is equal to, or even more 
than, the width of the terrace itself. This arrange- 
ment ensures perfect drainage, which is very salutary 
for such plantations. The soil is carefully prepared, 
and almost always sbaded bv large trees (Ficus, 
Tamarindus, Ehretia, Dobera, &c), planted in a row 
Many plantations are irrigated during the dry [season 
