tobacco juice kills almost every bug other than horned catapillars which are the ones that love to eat my tobacco leaves. You have to be very carefull if using on dogs or animals to dilute it pretty good it makes them very hyper and you dont want to OD the dog. It works better than most insectacides I have found for fleas and ants. No it doesnt harm grass or trees, but it can be very dangerous if spilled on your skin can make you have a Nicotine OD so be careful. wash hands often when using. Biggest advantage is it is free from the biproduct of the tobacco plants stems, scraps, and any tobacco that molds during curing proccess.