How do I get rid of leaf rollers?
The best way to control leaf rollers is by cutting the canna stalks down after a hard freeze and burning or trashing the debris. Do NOT compost the stalks. Eggs may be on the leaves and will overwinter in them and then hatch out in the spring.
You can also hand pick the caterpillars off the leaves and destroy them.
You can also use pesticides containing malathion, orthene, permethrin, or bacillus thuringiensis. Do NOT use sprays or systemics on cannas that will be used in the pond.