Answer: I always read pesticide labels twice before using the product. First to make sure the pest I'm targeting is listed on the label, and second to make sure the plant I'm going to use it on is also listed on the label. You've found from first-hand experience that not all products are safe on all plants. The damage may have been done by the chemicals in the product, or by the effect of sunshine on newly sprayed foliage. In either event, as long as it is otherwise healthy, your Michelia should produce new leaves to replace the damaged ones. Next time you find caterpillars munching away, try handpicking and destroying them, or using the botanical Bt (bacillus thuringiensis) which is safe to use on most plants and effectively controls caterpillars.
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