Answer: The leaf drop can be attributed to either the soap spray (which is a plant-derived fatty acid) or to the differences in temperature and light your crotons are now receiving. Some plants are more sensitive to insecticidal soaps than others. When the residue fatty acids remain on some leaves, they block the openings on the leaf surfaces, preventing the natural exchange of air. Next time you use insecticidal soap on sensitive plants, allow it to work for about 20 minutes and then hose it off with plain water. When plants are moved in from summering outdoors, the move should be gradual so the plants can adjust to the lower light levels, drier air and change in temperatures. Next time you move from indoors to out or vice versa, do it by exposing the plants to their new homes for just a few hours a day, increasing the time a few hours a day until your plants are living outdoors or indoors for 24 hours a day. This gradual move will help them adjust quickly.
The leaves your plants are losing will probably be replaced in a few weeks. If you don't see any new growth in a month, prune them back to encourage new growth.
Best wishes with your plants!
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