The best way to naturally control aphids that t have found it to start as early as possible. If you can top plants when buds form, before flowering, before July 10, there won't be excessive aphids pressure. It is important then to stop hornworms from eating the lamina. I mix Pyrethrins and neonicatanoids for worms. Neonicatanoids are now illegal in some states. Bifenthrin seems to work okay. Have to spray especially UNDERSIDES of leaves, and by simply inspection underleaf you can find the green monsters in plants with partly eaten leaves, pull them off and kill them by hand. I prefer to use non chemical control but in mid-July when bugs attack tobacco heavily they can quickly become overwhelming. Observe label intervals before picking or harvesting, and schedule pesticide use for as early as possible.