What Is Wrong With My Switchgrass?

Are the seedlings dying and the stems are girdled or rotted at the soil line?

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

Are there any blister-like lesions near the base of the plant and streaks on leaves?

Are the leaves curled and distorted?

Have the leaves been devoured?

Are the leaves discolored and distorted?

Are the leaves yellow, stems die back?

Are the leaves discolored, fine webbing may be present?

If your seedlings are falling over and the stems are girdled or rotted at the soil line, the most likely cause is a damping-off disease. Remove and destroy all infected plants. To prevent damping-off let the soil surface dry between waterings, thin seedlings to avoid overcrowding, and do not add nitrogen fertilizers until plants have developed leaves.

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.

Smut fungus attacks mostly young seedlings as the new leaves emerge. It causes blister-like lesions near the base of the plant and streaks on leaves. The streaks mature into black powdery spores. The fungus stunts the growth of the plants. More mature plants are not as susceptible. If the infection is mild, cut off and destroy all infected leaves. In more severe infections all you can do is destroy plants to stop smut from spreading.

Distorted and 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.

Some types of grasshoppers can become a problem for switchgrass. Grasshoppers devour the leaves of plants. Use a Bacillus thurigiensis (BT) spray or powder to control their population.

Discolored and distorted leaves are caused by leafhoppers. These small, green, or brown insects feed by sucking juices from leaves undersides. Leafhoppers may be the carriers of the Mosaic virus, so it is important to keep them in control. Insecticidal soap helps with severe infestations.

Stem borers are small caterpillars that cause stems to die back. As spring growth begins, you can easily spot borer-infested plants because the leaves look weak and sickly. The easiest control is to cut out and destroy infested plants as soon as you notice them.

Spider mites are known to cause problems for switchgrass. 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.