What Is Wrong With My Goldenrod (Solidago)?

Are the leaves greenish-yellow and the growth rate is poor?

Do the leaves have small, water-soaked spots?

Are the leaves covered with white powder?

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

Are the leaves stippled and distorted?

Do the leaves have large, ragged holes in them?

Are the leaves curled and yellow?

Are the leaves discolored, fine webbing may be present?

Are the leaves mottled with dark green?

Greenish yellow, strap-shaped leaves followed by a poor growth is caused by Aster yellows disease. There is no cure for Aster yellows, so the infected plants should be destroyed. Prevent the disease by controlling leafhoppers. Spray the plants with the insecticidal soap 3 times, once every 3 days.

Bacterial leaf spot causes circular water-soaked spots on leaves. These spots turn brownish-black and may spread to form large patches of dead tissue. To prevent the spread of this disease, avoid working around wet plants. Remove and destroy affected parts. Spray Bordeaux mix on remaining plants.

White, powdery patches on the leaves are caused by a fungal disease Powdery mildew. Powdery mildew usually appears in damp places. Encourage good air circulation around the affected plants by thining them and any surrounding plants. Water plants from bellow to keep foliage dry. Any affected leaves should be cut off and removed. Any commercial fungicidal spray will protect your plant from further infections.

Likely cause for these symptoms is a fungal disease - Rust. Provide good air circulation around plants by thining them. Avoid making leaves wet when watering. All infected leaves should be removed. Spray leaves with sulfur early in the season to prevent rust or to treat mild infections.

Aster leafhoppers are greenish-yellow, tiny insects that feed on leaf undersides, giving the foliage a finely mottled look. Leaves yellow, shrivel and drop. Besides injury from feeding, leafhoppers transmit the disease aster yellows. Use water or insecticidal soap sprays to dislodge nymphs. Encourage enemies such as big-eyed bugs and parasitic wasps. For control of severe infestations, spray plants with neem or pyrethrin.

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.

Distorted, curled leaves are caused by aphids. These tiny insects 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.

Spider mites are known to cause problems for goldenrods. 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.

Mottled or streaked leaves are caused by Mosaic virus. There is no cure for infected plants. Remove and destroy all flowers that have the symptoms of the mosaic virus. Mosaic virus is spread by aphids, so the best way of preventing the disease is to control these insects.

Spittlebugs will sometimes attack goldenrod plants. The insect produces a protective foam that looks like spit. The foam helps protect the insect from ultraviolet light, predators, and insecticides. Use a strong spray of water to wash the foam away. The resulting exposure to UV light will kill the insect and expose it to predators. A stronger spray of water may also remove the insect from the plant.