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 suggested 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 "sprayed over scale-insects produced no apparent effect" (Comstock). 2. _Ammonia._ Whether used pure (diluted) or in urine, damages the plants much more than it does the insects (Hubbard; Comstock). 3. _Ashes._ Powdered, or mixed with lime, salt, soot, &c. Of no value whatever (Hubbard; Personal experiment). 4. _Carbolic acid._ Of no avail, either as spray or brushed on, unless used in such strength as to seriously damage the tree (Hubbard; Riley; Comstock). 5. _Castor-oil._ Has been found efficacious in cleaning hawthorn-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 larvæ and adults, supposing it to be sufficiently 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 harmless to growing plants;" but "the cost is too great, except on a small scale, as in conservatories" (Comstock). 7. _Gasoline._ Seems to have been used in California on pear-trees: result, doubtful (New Zealand Parliamentary 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 coccineus_ (Alderton); in Nelson it is said to be used beneficially against _Icerya purchasi_. _It does not, however, kill the eggs with certainty_ (Personal experiment). Applied warm, and properly diluted, it may be recommended as a good remedy; but applications of it should be repeated. 9. _Kerosene._ Seemingly the most valuable of all remedies, when properly applied. "Almost the only substance which will certainly kill the eggs without at the same time destroying the plant" (Hubbard).