Answer: You may be dealing with geranium bud worms, which are difficult to control except by picking off the affected buds and destroying them. The worms hatch from eggs laid on the surface of the buds, and the larvae bores into the bud and eats its way out. While it's inside the bud, no chemical can reach it. I'd inspect the buds for a tiny little entrance hole and pick off the buds that are suspected of harboring worms.
If you can see caterpillars on the plants, and don't want to pick them off one by one, you may be able to control them with the botanical called Bt. It's a stomach poison and the caterpillars have to consume some before it takes effect, so expect continued feeding until the caterpillars have ingested enough to do them in. Be sure to read and follow the label directions.
Pinching is generally done with the fingers. To make a plant bushy, simply pinch off the very end of each stem. This will force new stems to grow farther down on the stem. When I was a new gardener I though pinching was an exact science. It really isn't. Just pinch the ends of the stems early in the season and you'll end up with a bushy plant that produces lots of flowers. Continued pinching throughout the growing season will renew the plant and provide even more blooms.
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