Problems With Canna Leaves

Insects

• Canna leaves first appear as narrow curls that gradually unfurl to large leaves. When the leaves remain tightly rolled and do not open, they may be infected with leaf rollers. Holes eaten through the leaves are usually signs of caterpillar or grasshopper pests. Spider mites and aphids may damage leaves. Control measures include applications of systemic insecticides or insecticidal soaps.

Diseases

• Canna leaves are vulnerable to diseases such as canna rust and viruses. Canna rust causes orange leaf spots. Mosaic virus causes irregular green or yellow splotches on leaves. Control requires removal of infected leaves and the use of a fungicide. Planting disease-resistant cultivars might prove helpful.

Slugs

• Tender canna leaves attract slugs and snails. Leaf holes, especially near the plant base, and slime trails on the plant usually indicate slug problems. Debris around the plant provides shelter for slugs. Slug bait may be necessary to combat heavy infestations.