Answer: Although aphids will such plant juices from the stem and tender new growth I would not expect them to cause browning of the flowers. The browning may be due to a fungal infection related to the weather, such as botrytis. Deadhead any discolored flowers as well as those that have faded and dispose of them in the trash to avoid sources of reinfection. Avoid handling the plants when they are wet. Aphids can be treated with ccommercially formulated insecticidal soap per the label directions. I hope this helps.
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