What Is Wrong With My Twinberry?

Are there any sunken areas in the wood of the branch, stem, or trunk that contains dead tissue?

Are the leaves covered with white powder?

Are the leaves rolled and chewed?

Are there any sunken, discolored spots on the leaves?

Are the leaves distorted and yellow?

Hypoxylon canker is a disease known to attack twinberry honeysuckles. Prune out and destroy dead branches and infested areas. Be sure to make pruning cuts at least 3 or 4 inches below the canker and disinfect pruners between cuts. Spray both the healthy and diseased sections of a tree with copper during and shortly after periods of excessive rain.

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 below to keep foliage dry. Any affected leaves should be cut off and removed. The appropriate fungicidal spray will protect your plant from further infections.

Rolled leaves are caused by leafrollers. These green caterpillars with brown heads feed on the enclosed leaves and buds. If the infestation isn't severe, handpick the rolled leaves with caterpillars. For severe infestations, the use of insecticides is the only way of controlling.

Sunken and discolored spots on leaves are caused by Four-lined plant bugs. These small yellow bugs have 4 black stripes on their wings. They are active in early summer. Control them by handpicking. Use pyrethrin on leaves for severe infestations.

Distorted, yellow 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.

Wandering, white or translucent tunnels in leaves are caused by aspen leafminers. Leafminers prefer young, tender foliage and cannot tunnel in hardened leaves. Avoid applying nitrogen fertilizer while populations are high, or the new growth will be severely damaged. As pruning too frequently can also stimulate new flush growth, avoid pruning live branches more than once a year, so that cycles of flush growth are uniform and short. Do not prune off leaves that have been mined—the undamaged areas of the leaf are still able to produce food for the tree.