Solving Canna Problems
| Canna Problems | |
|---|---|
| Symptom | Probable Cause |
| Leaves Chewed; Folded Over | Canna Leafrollers |
| Leaves Webbed Together; Discolored | Leaftiers |
| Holes In Leaves And Flowers | Japanese Beetles |
| Leaves Curled And Distorted | Aphids |
| Small Bumps On Leaves And Stems | Scale Insects |
| Buds and Flower Stalks Rotted | Canna Bud Rot |
Leaves Chewed, Folded Over Caused By Canna Leafrollers
Adult leafrollers are butterflies known as skippers. They damage cannas while in their caterpillar form. It is up to 1-3/4 inch long and green, with an orange head. As it chews a strip of leaf it causes it to fold over. Then it continues to feed from beneath this coverlet, skeletonizing the leaf. A fellow leafroller webs new leaves together before they have a chance to unroll. Control both by spraying canna leaves as the caterpillars appear with BT (Bacillus thuringiensis). Or, simply crush the caterpillars in their little hideaways with your thumb and forefinger. For more information see the file Controlling Leafroller
Leaves Webbed Together; Discolored Caused By Leaftiers
Celery leaftiers attack cannas. Adult leaftier moths are brown or gray, 1/4 to 1/2 inch long, with a 3/4 inch wingspan. Their larvae are caterpillars, 3/8 to 3/4 inch long, dark to light green or cream to yellow, with a white stripe running down their backs. The larvae protect themselves while feeding by webbing leaves together with strands of silk. This foliage becomes ragged and unsightly, turns brown and dies. Spray vulnerable plants with BT (Bacillus thuringiensis) before you expect the caterpillars to begin feeding. They will ingest it and die within a matter of days. Minor infestations can be controlled by handpicking the larvae, webbed hideouts and all.
Buds and Flower Stalks Rotted Caused By Canna Bud Rot
This bacterial disease produces watersoaked streaks and spots on new, unfolding canna leaves as well as older leaves. It then spreads to the flowers. A gummy sap may bleed from diseased areas on stalks. The condition is aggravated by overwatering, overcrowding and poor aeration. Destroy diseased plants. Select healthy tubers and dip these in a streptomycin solution before planting.