I am not so sure I would be quite so alarmist about nicotine. The LD50 of 50 mg is about what you would find in 5 cigarettes or maybe a half of a cigar and applies only if the entire amount is ingested at one time. Patrick was going to use 1 cigarette (extract); as it is unlikely that all of the extract would land on him, it is true that many of the intended victims and unintended as well are killed. Given that the plants are infested with harmful beasties and are not being controlled by beneficial insects, it is likely that no real damage to anything beneficial would occur.
As to TMV, unless he has tomatoes, cucumbers or the like (it is true that there are some ornamental flowers also susceptible), that if the tobacco, which has probably been inspected, and certainly cured, would not transmit TMV into his garden. With TMV in the environment for such a long time now, if it was easily transmitted into gardens, it would have been so for some time.
I hope that anyone considering using nicotine as a pest killer knows about these things and evaluates them as to their appropriateness in the garden.
While I am not a smoker, I do not fear its presence. There are many successful, smoking, gardners that I know.
I was just trying to add to the general knowledge, of course. The organic gardeners around here would have an infarction if anyone who even said the word malation in their presence. I use malathion all of the time to douse ant colonies......
Also TMV can be created in the laboratory, it is a chemical mutant rather than a virus it is so simple.......and so potent.
Of course, Patrick, you could take the baboon solution and they would pick them one by one and eat them....but baboon rentals are quite expensive!