Answer: The beetles might be Japanese beetles, which peak in mid to late July, if they have progressed as far west as you. There are also some other beetles that will feed on the blooms. Generally they are unsightly but do not harm the plant so much. Your local county extension may have suggestions for controlling them. However they can be hand picked early or late in the day and dropped into soapy water, or you might try using a spray containing neem to repel them. If you do spray, be sure to read and follow the label instructions.
The wrap arounds may be caused by one of the leaf roller pests that can bother cannas. Here is a photo.
These can be treated with Bt. You would also want to be very careful to clean up and destroy all of the old canna stems and foliage at the end of the season to try to limit the sources for reinfection next year. Also wash the rhizomes clean prior to storage, if you plan to keep them for next year.
If neither of the above seem right, you might consult with your local county extension to obtain a more specific diagnosis and based on knowing that, recommendations for what to do. Good luck with your cannas!
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