During heavy infestations, a rotation with contact and systemic fungicides can be implemented. Contact materials for rust management include mancozeb, chlorothalonil or coppers. Systemic materials include myclobutanil, kresoxim-methyl, triadimefon, triflumizole, azoxystrobin, trifloxystrobin, or pyraclostrobin.

Does Canna rust spread to other plants?

In extreme infections, the damage may not be contained to the leaves, but may migrate to the stems and flowers, causing discoloration, deterioration, and wilting. Once rust presents itself, all nearby cannas are vulnerable to its spread, especially if the damp weather persists.

What do you spray on cannas?

If you find leafrollers gnawing on your cannas, alternate spraying products with the active ingredients spinosad and Bacillus thuringiensis (Bt) every week, making sure to spray down into the rolled-up leaves where caterpillars hide.