Junkman said:
A tea made from tobacco juice sprayed on the lawn.
I'm not sure what type of "scrap chew" is available in England, but here in the US there are brands like MAIL POUCH, CHATTENUGA CHEW, and BEECHNUT. These are rough cut semi-moist tobaccos sold in a foil pouch. Dry tobaccos may work but I've never tried them, most dry tobacco is cut very fine and used for pipe or cigarette smoking, it would proabably take longer to steep, and certainly take longer to strain. The semi-moist scrap chews are ideal for making a strong tobacco tea that is an effective insecticide.
The drug you are trying to get to leach out of the tobacco is the nicotine. While Nicotine is addictive, it is not generally considered to be harmful to humans, it seems to be toxic to bugs. Take a large (3 to 5 gallon) clear jug, fill it with very warm water, allow the tobacco to steep in the jar, in the sun for at least 1 full day. Strain the liquid before you pour it into your sprayer.
If you also want to enhance the ability to REPEL other bugs, you can add minced garlic to the tobacco when you steep it. The longer you steep the garlic and tobacco the more concentrated the solution. If you let it sit for a couple days you can then mix it with water to double your batch.
If you want to spray this on shrubs, add a couple drops of liquid dish soap per gallon. By adding a couple drops of liquid soap it allows the solution to adhere to plant leaves, but this is unnecessary & counter productive if you are trying to get the solution down into the grass roots.
