This section is from the book "The Gardener's Monthly And Horticulturist V24", by Thomas Meehan. See also: Four-Season Harvest: Organic Vegetables from Your Home Garden All Year Long.
The following method, says the Revue Horticole, has given most satisfactory results, and the inventor, M. Boizard, gardener to Baron Rothschild at Paris, assures us that success is infallible - at least for three years, during which he has been experimenting with it it has been so with him. He says, " Having procured 2 quart's of tobacco juice, I boil it over a slow fire on a furnace in the house. An hour and a half or two hours afterwards, the liquid being reduced to about one-third its bulk, becomes viscid and almost solid, when, after having diluted it into 1 quart or 1-½ quarts of water, I boil it more quickly until all get converted into vapor and fixed in the form of dew on every portion of the plants. I remarked no damage done, not even amongst the most tender plants, such as Adiantums, young plants of Blechnum Braziliense, Coleus, etc. Some young fronds of Adiantum alone suffered, but it should be added that they were on the stages." If danger were apprehended in the case of certain plants, they might be taken out, or their safety assured by means of paper caps; and if it was a question of flowers or fruits, similar precautions might be taken to preserve them.
M. Boizard assures us that no insects can resist this treatment and that the greater portion of them do not appear again for six months. In the case of such as reappear quickly, it is easy to renew the operation, but then 1 quart of tobacco juice and 1 quart water will suffice. This method is as economical as any other, and M. Boizard says that it is possible to remain in the house during the operation without being inconvenienced thereby. - /. Corn-hill in Garden).