Why Are The Leaves Of Some Lilies In My Garden Decaying?

Are the leaves yellow-colored, plants and bulbs might wilt or decay?

Are the leaves yellow and distorted, bulbs might be decaying?

Do the leaves have holes in them? Flowers might be with holes also.

Are the leaves, stems, and buds distorted and sticky to the touch?

Do the leaves have orange or reddish-brown spots on them? Buds may be rotted.

Are the leaves mottled and does the plant looks stunted?

Are the leaves pale on their upper side and are there any dusty blisters on the undersides?

Yellow leaves together with wilting of the plant are caused by bacterial or fungal rots. You can control rots if you plant lilies in well-drained soil, in a place with good air circulation. When watering, avoid excess water on the foliage. Cultivate lilies with care to avoid mechanical injuries.

Yellow and distorted leaves and decayed bulbs are caused by insects - Bulb mites. These tiny, whitish mites feed in groups on bulbs. Infested bulbs have corky, brown spots that become powdery. Bulb mites are attracted to damaged or rot­ting bulbs but can move to healthy ones. Dig and destroy severely infested lilies, solarize the soil before planting in the previously infested ground.

Holes in leaves and/or flowers usually indicate some species of leaf-eating beetles. Japanese beetles are the most common pest that makes holes in leaves. Adults of these insects devour leaves, stalks, and flowers of nearly 300 plant species. Their larvae feed on the roots of the plants. Handpick adult beetles into a can of soapy water but make sure to wear gloves as Japanese beetles are blister beetles. Apply parasitic nematodes to the soil to limit beetle grub populations. Use pyrethrin powder or neem oil as a last resort.

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

A variety of viruses cause yellowed, mottled, or streaked leaves and stunted stems on lilies. There is no cure for viral diseases so the only thing you can do is dig up and destroy all infected lilies so the disease doesn't spread. To prevent viral diseases make sure to control small insects like aphids, mites, leafhoppers, etc. as they are the most likely carriers of viruses.

Likely cause for these symptoms is a fungal disease - Rust. Provide good air circulation around plants by thining them.

Some environmental issues might have caused your lilies unhealthy look. Lilies love full sun or partial shade and deep, moist but well-drained soil, rich in humus. Planting them in such a place to avoid environmental problems. Nitrogen deficiency is known to make leaves yellow. Mulch lilies with several inches of compost to ensure them with enough nutrients and to keep the soil cool and evenly moist.