Canna Leaf Rollers

• Canna leaf rollers (Calpodes ethlius), as well as the lesser canna leaf roller (Geshna canalis) and Brazilian skippers, are caterpillars that feed on canna foliage, eating holes in straight rows on leaves. Most caterpillars roll or tie leaf edges together using a cocoon-like web and feed protected on the inside. Infested young leaves are often so damaged that they cannot open and may die. Heavily infested plants become unsightly and may not be able to bloom. Cut off and destroy infested foliage or unfurl leaves and remove the caterpillars. Additional control options include systemic insecticides, pyrethroids, insecticidal soaps and sprays of Bacillus thuringiensis.
  
  

Slugs and Snails

• Slugs and snails are pests of canna, preferring to feed on tender, young leaves that are not yet unfurled. Slugs and snails chew large holes in foliage and leave a slime trail where they travel. Removing debris around the lily will eliminate the daytime hiding places that these nocturnal pests require. Commercially available baits are also effective control options.
  
  

Grasshoppers

• Grasshoppers tend to congregate where there is adequate food and can entirely defoliate plants. A grasshopper infestation can be treated with a number of commercially available insecticidal, biological or botanical products. Floating row covers can be placed over valued lilies to prevent grasshopper feeding damage.
  
  

Additional Possible Problems

• Parallel tears in canna leaves are sometimes misidentified as insect damage. If no insects or insect droppings are present, the parallel tears are likely caused by water stress following a period of abundant water. This type of damage cannot be corrected but can be prevented by supplying cannas with water during periods of dry weather.