I am sorry for this delayed reply to your gardening question. We are transitioning to a new Q&A system and your question was unfortunately lost in the transition. I have discovered it now and hope this reply is not too late to be of help.
If you don't see any damage the beetle is just passing by and using the bloom for shelter. There is however more than one beetle that may be found feeding on a rose bloom. The following web site lists several with photos including Japanese beetle, Chinese rose beetle, and hoplia beetle.
If it is feeding on your roses you may purchase an appropriate product for controlling them at your local Home Depot. Products with orthene or carbaryl are among many effective options.
Thanks for the question. Please stop in again soon!
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