…Fungus gnats, aphids and other garden pests. Especially seems to be a valuable companion plant for indoor gardening where the absence of UV light and larger predatory insects (like ladybugs) allows some of them to proliferate unchecked.
Woodland Tobacco, Nicotiana sylvestris, an ancestral hardy species, is the best of the Nicotiana genus in my opinion. The sticky resinous leaves attract the pests where they remain to die. Are they immobilized first or absorb some nicotine and other Tobacco pathogens or succumb to a combination of effects? For an indoor gardener it does not matter.
The seeds are small and slow to reach working size. The one tiny plant in the foreground and the two behind are Woodland tobacco. There are already 14 dead fungus gnats on the larger plants.
This tobacco in a quart pot is doing its companion job well. Potted tobaccos can be moved around easily to be positioned beside any plant where aphids or fungus gnats appear. In the top left corner is a leaf from Japanese mugwort, Yomogi. So far no pest insects there but to the right and nearby are French tarragon that seem to be more susceptible.
I have grown a half dozen other Tobacco species. The next two in order of companion plant potentcy are N rustica, “Hopi” Tobacco in some seed catalogs, and N alata, “Jasmine” Tobacco. Hopi Tobacco has large seeds and grows to size faster but also bolts quickly to flower but the flowers don’t amount to much. N alata is slow to bolt, like the Woodland Tobacco, and also like the Woodland species when it does flower has beautiful persistent long trumpet shaped blossoms. Both emit a jasmine fragrance from dusk to dawn.
For a faster start rather than planting only Woodland Tobacco to catch up during the indoor season, an indoor gardener might plant Hopi Tobacco and Woodland Tobacco seeds as early as reasonable before moving or starting other plants indoors.
bountifulgardens.com sells seeds of Woodland Tobacco and Hopi Tobacco.
More info about historic and counter-conventional medicinal uses of Tobacco: