Canna leaf roller ??? for Abutilon or anybody

My cannas this year were miserable. It wasn't until late in the season that I stumbled across something that seemed to be the likely cause of my problem: leaf rollers. Many of the leaves never unfurled, and the flower buds emerged blackened, shriveled and disfigured.

Sigh. These were RIGHT next to my driveway, and they looked terrible.

I'm not sure I even want to fool with these canna tubers next year. They were supposed to be 'Rosever' with pretty rose-colored blooms and bronze foliage; instead the few sorry-looking flowers that appeared were orange-red, and the foliage was plain-jane green. (They DID stay dwarf, which is about the only bright spot in this sad, sad tale.)

Assuming I can't bring myself to let them rot in the ground, here are my questions:

1) Will the leaf roller problem resolve itself if I apply insecticide next year, or do I need to do something special to treat the tubers when I lift them?

2) Since I DO want to put SOME cannas in the same spot next year, is it possible that the ones that rotted LAST year were harboring the leaf rollers THIS year? (If so, this was a miserable "lesson learned".)

3) Is there a praetoria/striped foliage variety that stays dwarf? (I AM making some plans for next year :)

Terry, did you also post this in Garden Foes?
Sorry I have no help to offer...

Terry; hope the following information helps you out somewhat.

You Canna if You Wanna!


Cannas are also bashed because of a little pest called the canna leaf roller. He's the little larva of the skipper butterfly known for trick shooting straight rows of holes into the leaves. Heck, if we threw out every plant that had a pest problem we wouldn't be growing periwinkles, hibiscus, tomatoes, roses, azaleas, passion vines, oak trees, fruits trees, etc... I don't even use insecticide for canna leaf rollers. Whenever the foliage looks ragged from insects or our habitually tough climate, I just cut them to the ground, water and fertilize them, and PRESTO, brand new plants and flowers in a matter of weeks. It doesn't matter if you use a machete, string trimmer, brush cutter, tractor, or a flame thrower. The amazing results are still the same.(information taken from the following link)
http://www.plantanswers.com/parsons/CANNA.htm

Insects such as the canna leaf roller (Calpodes ethlius), which will turn into the small golden-brown Brazilian Skipper butterfly, may be controlled on the leaves by applying a solution of Bt (Bacillus thuringiensis), insecticidal soap, or other chemical control once a week. Apply the insecticide around and into the young leaves while they are still rolled up. Check older leaves for the tell-tale silken threads leaf-rollers spin to keep the leaves closed. Unroll leaves carefully if necessary and remove the caterpillars. (this taken from following link)
http://aggie-horticulture.tamu.edu/southerngarden/cannas.html

Terry, I was told in the fall to cut all the foliage off and remove it. Next spring after the canna's put on their new foliage dust it good with the Dipel and then only use if you see leaf roller problem. I was told you only need to use it 2 or maybe 3 times a year.

So this year I'm going to remove all the old foliage and hopefully next yr I won't have the leaf rollers.