maybe spider mites????

all of my problems have been from Jap beetles they just eat eat and eat...

Re. spider mites... I just can't catch any insect life on the plants except a passing bee or wasp.

Re. Japanese Beetles! These buggers are right up my alley! (Never was bothered by mass infestation until three years ago, I could pick off enough by hand.) Bought two lure traps, put one each side of the beds... good results. Except... the traps lure more beetles since the pheramone lure drifts with air currents and alerts horny beetles from the whole neighborhood.

I asked my local trusted Adams' Fairacre Farms experts and they suggested Sevin with a "sticker". Being frugal (cheap) on some things I mixed gallon batch of Sevin as per instructions on container and added my own "sticker", one half teaspoon of dish detergent. (Sevin contains a sticking agent but it will roll right off waxy canna leaves.)

I applied it wetting the plants and blossoms and in an hour all the beetles that were on the plants were sick or dying. Next day... NO living beetles. Since then it takes about 1 application a week for approx. 3 weeks to completely free the plants for a season. Rain will slightly diminish the effect but a gallon goes a loooong way and with the sticker resists washing off pretty well. I won't use any lures anymore, they find my plants OK without advertising! :)>

You have leaf rollers - all the classic symptoms are there.

I use an Ortho spray, and it works well. Some people like powder, because it stays around longer, but it looks like %^$#*#!& on the cannas.