As a gardener and elderberry enthusiast, I often get questions from readers about dealing with pests like borers on their American elderberry shrubs Borers can certainly be destructive if left unchecked, but there are effective strategies to get rid of them while keeping your elderberry plants happy and producing. In this comprehensive guide, I’ll share my tips and advice for identifying, preventing, and managing borer infestations on American elderberries.
What Are Borers and Why Target Elderberries?
Borers are the larval form of certain moths and beetles that feed inside plant stems and branches. Some common species that attack elderberries are the elder borer, red-headed ash borer, and bronzed borer. They likely target elderberries due to the soft inner wood. The larvae bore tunnels and feed on inner tissue, disrupting water and nutrient transport. This causes dieback, stunting, and even death in severe cases.
Adult borers lay eggs on plant surfaces in late spring and summer The eggs hatch into larvae which immediately burrow into stems. They overwinter inside plant tissue, pupate in spring, then emerge as adult moths/beetles, repeating the cycle
Recognizing Borer Infestations
Be vigilant in monitoring plants from late spring through fall for early detection:
- Small holes on stems with frass (sawdust-like excrement).
- Weak, dying, wilting stems and branches.
- Swollen or cracked lenticels.
- Premature fall coloration/leaf drop.
Act promptly if you spot these signs to prevent spread.
Effective Borer Control Methods
Cultural Practices
Good maintenance goes a long way in deterring borers. Actions like pruning out dead wood, watering adequately, and fertilizing appropriately keep plants robust. Stressed plants attract borers.
Physical Barriers
Wrapping stems with aluminum foil, wax paper, or burlap can block egg-laying. Apply in early spring before adult emergence.
Biological Control
Encourage beneficial insects like parasitic wasps that destroy borer larvae. Also attract insectivorous birds.
Targeted Sprays
Insecticidal soaps, neem oil, spinosad, Bt-k are organic options. Use per label instructions during vulnerable times. Avoid harming pollinators.
Removal and Sanitation
Cutting out infested stems and promptly disposing debris removes borers from site and reduces spread. Sterilize tools after.
Preventing Borers in Elderberries Long-Term
Here are some key preventative measures I recommend:
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Select borer-resistant elderberry cultivars like Johns, Scotia, York, among others.
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Properly space plants to allow air circulation. Crowding stresses plants.
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Use plastic tree guards or hardware cloth around plant bases as physical barriers.
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Maintain 2-4 inch mulch layer to retain moisture and nutrition.
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Water deeply and regularly, especially during summer. Drought-stressed plants attract pests.
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Fertilize plants in early spring and again after fruiting per soil test recommendations. Proper nutrients support health.
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Prune every 1-3 years to stimulate new growth. Removing 20% is sufficient.
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Amphibians & Reptiles of Northwest Missouri
How To Treat Tree Borers.
How do you get rid of elderberry borers?
The use of horticultural oils or insecticidal soaps to treat outbreaks is recommended. Some miticides may be useful as well. The larvae of this beetle bore into elderberry canes, while the adult form feeds on leaves and flowers. Sometimes referred to as elder borers, Desmocerus palliatus has a two-way impact on elderberry plants.
Do elderberry plants have bugs?
Don’t panic if you notice a couple of elderberry bugs hanging out on your plants. These are typically easy to remove with pesticides or avoid altogether with floating row covers. Some of the most common pests that you find on elderberry plants are cane borers, aphids, and thrips. These are all winged insects that feast on the leaves of your plants.
How do I know if my elderberry has borers?
Sometimes referred to as elder borers, Desmocerus palliatus has a two-way impact on elderberry plants. The adults feed on leaves and flowers, while their larval form bores into stems and roots. If you don’t see the adult form first, you can usually tell the larvae are present by small piles of sawdust at the base of older canes.
What pests eat elderberry plants?
Some of the most common pests that you find on elderberry plants are cane borers, aphids, and thrips. These are all winged insects that feast on the leaves of your plants. Some are more challenging to spot than others, so make sure you check the underside of the leaves.