I have used dish soap in water as a dip with good results; I had a bad spider mite problem and was able to clear them with dish soap, I actually dipped my plants in water with a tiny amount of dish soap and then washed the soapy water off straight after dipping.
Dish soap works because it is a surfactant which lowers the surface tension of water making it wetter, this in turn prevents bugs (especially ones with hairs) from surviving in a bubble and hence they drown.
So as you can see it is a contact killer and requires the spray to contact the bug, once the bug is covered it dies, although any eggs wont be killed and you need to re-spray / dip once the eggs have hatched; knowing the life cycle of the bug is the key.
I actually tested this by watching this under a microscope, I tested milk and that did not kill the bugs but dish soap did; having said all that, your problem looks to be more like either slugs or caterpillars or maybe something else.
If you see slug trails on your plants then you have a slug problem and are best to try and trap them with beer traps or if its caterpillars from moths then you should have a barrier like netting over your plants; it is good practice to keep netting over plants that are outside.
Another thing you can use to keep bugs away is Rhubarb leaves which contain Oxalic Acid and are poisonous (never eat Rhubarb leaves), placing the leaves on the ground around the base of the plant will keep most crawling insect away.
I feel I should warn you against using tobacco as it can harbor a virus called Tobacco Mosaic Virus (TMV) which can infect your plants if you havent boiled the tobacco for long enough.
If you do use dish soap make sure it doesnt contain bleach and isnt antibacterial; and good luck.
Dish soap works because it is a surfactant which lowers the surface tension of water making it wetter, this in turn prevents bugs (especially ones with hairs) from surviving in a bubble and hence they drown.
So as you can see it is a contact killer and requires the spray to contact the bug, once the bug is covered it dies, although any eggs wont be killed and you need to re-spray / dip once the eggs have hatched; knowing the life cycle of the bug is the key.
I actually tested this by watching this under a microscope, I tested milk and that did not kill the bugs but dish soap did; having said all that, your problem looks to be more like either slugs or caterpillars or maybe something else.
If you see slug trails on your plants then you have a slug problem and are best to try and trap them with beer traps or if its caterpillars from moths then you should have a barrier like netting over your plants; it is good practice to keep netting over plants that are outside.
Another thing you can use to keep bugs away is Rhubarb leaves which contain Oxalic Acid and are poisonous (never eat Rhubarb leaves), placing the leaves on the ground around the base of the plant will keep most crawling insect away.
I feel I should warn you against using tobacco as it can harbor a virus called Tobacco Mosaic Virus (TMV) which can infect your plants if you havent boiled the tobacco for long enough.
If you do use dish soap make sure it doesnt contain bleach and isnt antibacterial; and good luck.