Answer: This can be caused by a variety of reasons including overly dry soil (it should be evenly moist, not sopping wet and not dried out), spray toxicity or reaction to a spray, pests such as thrips, or a fungal infection. I would suggest you consult with your local county extension to obtain a specific identification of the problem. Based on knowing that, you will be able to decide how to treat them. I'm sorry I can't be more specific long distance.
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