Elderberry plants are valued for their ornamental appeal and bountiful dark berries, often used in syrups, jams, and wines. Like all cultivated plants, elderberries are susceptible to various insect and arthropod pests that, if left unchecked, may reduce vigor and yield. Protecting these plants from pest damage helps ensure a healthy harvest and promotes their longevity.
Common Elderberry Pests
Aphids are small, sap-sucking insects that commonly infest elderberry plants, often appearing in dense clusters on new growth and the undersides of leaves. These pests use piercing mouthparts to extract plant fluids, which can lead to distorted foliage, stunted growth, and leaf curling. Aphids also excrete a sticky substance called honeydew, which can attract ants and lead to the development of sooty mold on leaves.
The elderberry borer, the larval stage of a longhorned beetle, damages canes by tunneling. This internal feeding can result in wilting tips and lead to cane dieback. Signs of borer activity include lumpy or swollen canes and round exit holes.
Japanese beetles skeletonize elderberry leaves by feeding on the tissue between the veins. These iridescent green and copper beetles emerge in late spring or early summer and can cause significant defoliation. Their feeding habits can impact the plant’s ability to photosynthesize effectively.
Spider mites, particularly eriophyid mites, are tiny arthropods that distort and pucker elderberry leaves. Their feeding results in symptoms such as inward leaflet curl, stunted, and misshapen foliage with interveinal discoloration. Heavy infestations can reduce plant vigor.
Sawfly larvae, the larval stage of a wasp, feed on elderberry leaves. A significant infestation can lead to complete defoliation of sections of the plant. These larvae quickly consume leaf tissue, impacting plant health and productivity.
Stink bugs are shield-shaped insects that feed on elderberry fruits by sucking out plant juices. Both adult and nymph stages can cause damage, leading to deformed or shriveled berries. They often feed on immature green fruit, affecting fruit development and yield.
Identifying Pest Infestations
Changes in elderberry foliage often provide the first indication of a pest problem. Leaves may show discoloration, such as yellowing or browning, or exhibit unusual patterns like holes, chewed edges, or a skeletonized appearance. Distorted growth, including curled, stunted, or misshapen leaves and shoots, also suggests pest activity.
Sticky residue on leaves and stems, known as honeydew, is a common sign of sap-sucking insects like aphids or soft scales. This sugary excretion can lead to black sooty mold, impeding photosynthesis. Fine webbing on the undersides of leaves or between branches indicates spider mite activity.
Examining stems and canes can reveal other pest issues. Swellings, splits, or holes in the bark may point to borers tunneling within the plant. Wilting of individual branches or entire sections of the plant suggests internal damage or severe sap depletion.
Visible insects or their eggs on plant surfaces confirm an infestation. Regular inspection of both the upper and lower leaf surfaces, as well as stems and developing fruits, helps in early detection. Recognizing these general symptoms allows for timely intervention before pest populations become overwhelming.
Managing Elderberry Pests
Effective management of elderberry pests begins with proactive measures to promote plant health and deter infestations. Proper planting conditions, including well-drained soil and adequate sunlight, help plants resist pest pressures. Moderate and consistent watering also supports plant vigor, making elderberries less susceptible to attack.
Cultural practices play a significant role in preventing pest problems. Annual pruning in late winter or early spring helps remove dead, damaged, or weak canes that might attract borers or harbor overwintering pests. Removing older canes encourages new, more productive growth and improves air circulation, which can deter some pests.
Organic and natural control methods offer environmentally sensitive options for addressing pest issues. Hand-picking larger pests like Japanese beetles and dropping them into soapy water is effective for smaller infestations. A strong jet of water from a garden hose can dislodge aphids and spider mites from leaves.
Insecticidal soaps and neem oil are popular organic sprays that control a range of soft-bodied pests. Insecticidal soaps work by disrupting the insect’s cell membranes, while neem oil acts as an antifeedant and growth regulator. These products should be applied thoroughly, covering all affected plant surfaces, especially the undersides of leaves.
Encouraging beneficial insects, such as ladybugs and lacewings, provides natural pest control as they prey on aphids and other small pests. Planting a diversity of flowering plants nearby can attract these helpful predators to the garden. This biological control reduces reliance on other interventions.
Chemical controls are generally considered a last resort, particularly if elderberries are grown for fruit consumption. If chemical intervention becomes necessary, it is important to accurately identify the pest and choose a product specifically labeled for that pest and for use on elderberry plants. Always read and follow all label directions, paying close attention to application rates, safety precautions, and pre-harvest intervals to protect both the plant and the environment.