Q.Canna Lily pests
On the above article I did not see any reference to Japanese beetles. They are really attracted to the blossoms. I’m not sure if the Japanese Beetle lays eggs on the leaves (late spring)that hatch on the leaves (mid summer)causing leaf disfiguration. Some leaves roll up looking ugly with what appears to be a row of sutures holding it closed. The sutures are silky and easily broken. After breaking the sutures, the leaf can be unrolled revealing a worm (or larvae) approximately 1/2 ” long. The leaf interior is streaked brown and with residue from the pest. This all makes for an otherwise beautiful plant to become from less desirable to ugly. The question is; is this connected to the Japanese Beetle….or…. if not, what is it and how can it be controlled?
The rolled leaf is likely a caterpillar issue.
https://www.gardeningknowhow.com/ornamental/bulbs/canna/managing-canna-lily-pests.htm