A very effective control for aphids, mealybugs and other 'suckers' is a simple soap solution.
Almost any real soap can be used, (soap, not detergents) but you don't need moisturizers, scents and so on, so that will limit your soap choices when dealing with bar soarps. But it has been shown that potassium based soaps are even more effective than sodium (Potassium hydroxide lye as opposed to sodium hydroxide lye used to make the soap), which generally means a liquid soap...liquid castile soaps and Murphy's Oil soap fall in that category.
Mix 1 TBS of the soap (liquid...if bar soap, it needs to be liquified first) per quart of clean water in a spray bottle and cover the bugs well. Test a small leaf first, as some plants are more sensitive and can suffer from leaf burn.
Also, a strong jet of water can be used to wash minor infestations away.