34 
ey 
16. 
We 
18. 
ne: 
20. 
21. 
INSECTS NOXIOUS TO AGRICULTURE. 
to be one of the best remedies against the larve 
and adult insects—proportions from 1b. to $lb. soap 
to one gallon of water (Comstock ; Hubbard; Personal 
experiment). 
Soda, caustic. Strongly recommended by many persons. 
It injures the tree, and does not kill the eggs—two 
things which are decidedly against its use. Gar- 
deners may have been led to employ it from finding 
that in some instances it clears away the black 
fungus-growths (Chap. III.), and imagining this to be 
a clearance also of the scales. 
Soda, silicate. Kills some insects, but no eggs, and in- 
jures the tree (Hubbard). 
Sulphate of iron. ‘‘A common ingredient in patent 
remedies;”? most injurious to vegetation. It does not 
affect scale-insects (Hubbard). 
Sulphur. Another substance, the object of a kind of 
superstitious veneration amongst gardeners. It is 
excellent against fungoid growth, but of little value 
against scale-insects. Here, again, the clearing of the 
black fungus has probably been taken to mean also the 
destruction of the insects (Hubbard ; Comstock; Per- 
sonal experiment). Comstock says that in America 
people often bore holes in their trees and stuff them 
with sulphur, under the notion that the substance 
will be taken up by the sap, and poison the insects : 
quite a futile idea, 
Sulphur and lime. A dangerous compound, and useless 
unless apphed in such strength as to kill the tree. 
Its fumes are poisonous, and it may seriously injure 
the face and hands (Hubbard). 
Sulphur and snuff. Tiqual parts mixed and dusted over 
Lecanium hesperidum on a wet day were quite suc- 
cessful (Comstock). But the mixture would be too 
expensive except for conservatory plants, and doubt- 
less the snuff alone would be quite as efficacious. 
Sulphuric acid. “ Kiiled nearly all the scale-insects, 
and very nearly killed the tree’? (Hubbard). No 
mention is made of its action on the eggs. 
. Soot. Useless (Hubbard ; Comstock ; Personal experi- 
ment). 
