Dish soap works best for treating aphids. Even a strong stream of water from a hose is often enough to knock aphids off.

Aphids are weak and dumb, but ants help them get into the sheltered crevices where tender buds form. Aphids cannot climb on slippery surfaces and dislike strong scents.

Other pests you will have to learn what works best. Ants cannot walk over a barrier of dry diatomaceous earth; it kills them.