30 
INSECTS NOXIOUS TO AGRICULTURE. 
is believed that the information here given may be accepted and 
relied on. 
Some of the substances here given are manifestly unsuitable 
for general use on account of their expense, at any rate in the 
open air, 
Yet it is well to include them, as they are all sug- 
gested in some work or other, or in the replies of gardeners and 
fruit-growers to parliamentary inquiries; and the objections to 
them ought also to be known :— 
1. Alcohol. Will certainly kill any individual insect; but 
9 
~ 
co 
“sprayed over scale-imsects produced no apparent 
effect ””? (Comstock). 
. Ammonia. Whether used pure (diluted) or in urine, 
damages the plants much more than it does the 
insects (Hubbard ; Comstock). 
. Ashes. Powdered, or mixed with lime, salt, soot, &e. Of 
no value whatever (Hubbard ; Personal experiment). 
4. Carbolic acid. Of no avail, either as spray or brushed 
or 
on, unless used im such strength as to seriously 
damage the tree (Hubbard; Riley ; Comstock). 
. Castor-oil. Has been found efficacious in cleaning haw- 
thorn-trees at the Agricultural College, Lincoln (T. 
Kirk). It was mixed with soot for some unexplained 
reason. The time of the year when it was applied is not 
stated ; but the author’s experiments seem to show that 
castor-oil does not effectually kill the eggs. Still, it is 
doubtless a valuable remedy if applied repeatedly, so 
as to kill larve and adults, supposing it to be suffi- 
ciently cheap. 
6. Cole’s Insect-exterminator. Apparently a mixture of about 
2 parts of “green soap” with 100 parts of strong 
alcohol. It is “‘ effectual as an insecticide, and harm- 
less to growing plants ;” but “the cost is too great, 
except on a small scale, as in conservatories ” (Com- 
stock). 
7. Gasoline. Seems to have been used in California on 
pear-trees: result, doubtful (New Zealand Parlia- 
mentary Papers: Codlin Moth Committee Report, 
1885, page 8). 
8. Gishurst compound. Very favourably spoken of in many 
quarters. In New South Wales it has been found 
efficacious on orange-trees against <Aspidiotus coc- 
