Why Do My Daylilies Look Unhealthy?

Have the flower buds died, stems have corky lesions on them?

Are the leaves stippled, reddish or yellow with fine webbing?

Are the leaves, stems and buds distorted?

Do the leaves have elongated yellow streaks along the leaf mid-vein followed by browning?

Do the leaves have yellow to brown streaks on the leaves along with numerous, small yellow spots?

Is the plant stunted, leaves yellowed and the roots have lesions on them?

Have the leaves been tunneled?

Do the leaves have large, ragged holes in them?

Flower thrips are tiny insects that occasionally infest daylilies, feeding on buds, stem tips and flowers. Infested plants have distorted blooms and in severe cases, flower stalks fail to develop. Thrips are difficult to control because they burrow into plant tissue. Use blue sticky traps to monitor populations and trap pests. Pick off and destroy infested plant parts and encourage natural predators such as pirate bugs, lacewings and lady beetles.

Spider mites often cause problems for daylilies. Hose off plants when symptoms first appear. A strong stream knocks mites off plants and may give control. Introduce predatory mites. For severe infestations, spray plants with insecticidal soap or pyrethrin.

Distorted leaves, stems and buds are caused by aphids. These tiny insects can vary in color, green, pink, black, gray and completely white. They cluster under leaves and on growing tips where they feed on plant sap. Leaves, stems and buds get distorted and later leaves and flowers drop from the plant. You can control them by washing them off the plant with water spray. Insecticidal soap should be used with severe infestations.

Daylily leaf streak is caused by the fungus Aureobasidium microstictum. The symptoms usually develop from the leaf tip downward. The infected leaves may wither and die completely. Infected daylilies should be isolated from healthy plants. Avoid overhead irrigation. In the fall, remove dead foliage from around the base of the plants and dispose of the clippings.

Yellow to brown streaks on the leaves along with numerous, small yellow spots are caused by the fungal disease - Daylily rust. Leaves may yellow and die. To control this disease, rake up and destroy fallen leaves. Where the problem is severe, spray with copper.

These symptoms are caused by root-knot nematodes. Prevent root-knot nematodes by applying chitin or introducing parasitic nematodes to the soil before planting. Another preventative method is fertilizing daylilies with fish emulsion diluted in water which is then poured on the soil as a drench. It repels nematodes.

These symptoms are usually caused by Daylily leafminers. These tiny pale yellow fly larvae feed within the leaves in meandering mines that become wider as the larvae grow. Prune off and destroy all infested leaves. Remove debris in fall because it might contain overwintering leafminers. Introducing parasitic wasps is a very effective method of controlling leafminers.

Large, ragged holes in the leaves are caused by slugs and snails. Slugs and snails feed on the plant leaves usually at night. To control slugs and snails use diatomaceous earth around your plants. You can also handpick them during the night or use shallow dishes filled with beer as a trap.

If the plant suddenly wilts and is rotted at the base of the flowers, the problem may be the bacterial disease - Soft rot. Remove and destroy infected plants. Do not replant daylilies in that area.