Nicotiana, whether in the form of snuff, or its decoction in water, or its smoke whilst burning, is very destructive to insects.

Tobacco paper is paper saturated with the decoction of tobacco, and when burnt emits a fume nearly as strong. It is an easy mode of generating the smoke. Whenever plants are smoked they should be done so on two following nights, and then be syringed the following morning. Mr. Cameron says, - "I have always found tobacco paper the most efficacious substance to fumigate with for destroying the aphis without doing any injury to the plants; if the house is not filled too rapidly with smoke, and is allowed to reach the glass, without coming in contact with any of the plants, it then descends as it cools, without doing any injury. Plants fumigated in frames, or under hand-glasses, are most liable to be injured by the heat of the smoke, if not done cautiously. There is a spurious kind of tobacco paper sometimes offered in spring by the tobacconists, apparently made to meet the increased demand, and this kind of paper will bring the leaves off plants, without killing many of the aphides. It is of a lighter color than the genuine sort, and may be readily detected by the smell being very different. Foliage should be perfectly dry when a house is fumigated, and should not be syringed till nest morning.

If plants are syringed immediately after fumigation, many of the aphides will recover even where they have dropped off the plants, a fact which any one may soon prove after fumigating a house." - Gard. Chron.

Another very simple mode of fumigating plants in frames, and under hand-glasses turned over them for the purpose, is as follows: - "Dissolve a tablespoonful of saltpetre in a pint of water; take pieces of the coarsest brown paper, six inches wide, and ten inches long, steep them thoroughly in the solution, dry them and keep till wanted. To fumigate, roll one of the pieces into a pipe like a cigar, leaving the hollow half an inch in diameter, which fill with tobacco, twist one end and stick it into the soil, light the other, and it will burn gradually away for an hour or more".

Tobacco smoke should not be admitted to fruit trees when in bloom, nor when the fruit is ripening, as it imparts to them a flavour. See Fumigating.

Tobacco Water is usually made from what is known as Tobacconists' Liquor, being a liquor expressed by them, and full of ammonia and the acrid oil of the plant. To every gallon of this add five gallons of water. This mixture with Read's garden syringe may be sprinkled over the trees, putting it on with the finest rose, and being careful to wet all the leaves. This operation is to be performed only in the hottest sunshine, as the effect is then much greater than when the weather is dull; five gallons of liquor reduced as above stated, cleanses seventeen peach and nectarine trees, averaging seventeen feet in length, and twelve in height. The black glutinous aphis, provincially called blight, so destructive to the cherry trees, and in fact every species of aphis, is destroyed in the same way with equal facility; the grubs which attack the apricot, may be destroyed almost instantly by immersing the leaves infested in this liquor. - Gard. Mag.

As the tobacconists' liquor cannot be obtained always, tobacco water may be, in such case, made by pouring half a gallon of boiling water upon one ounce of strong tobacco, and allowing it to remain until cold, and then strained.