Arrowwood viburnum (Viburnum dentatum) is a hardy, low-maintenance shrub beloved for its clusters of white blooms and vibrant fall berries. However these popular shrubs are prone to attacks by wood-boring insects that can seriously damage and even kill affected plants. Learning how to get rid of borers on arrowwood viburnum is key to protecting the health and longevity of this beautiful addition to any landscape.
Identifying a Borer Infestation
The first step in managing viburnum borers is learning to recognize the signs of an infestation Watch for these common symptoms
- Wilting, yellowing, or curling leaves
- Small holes in trunk or branches
- Sawdust-like frass around base of plant
- Evidence of tunnels under bark
- Branch dieback
Two species typically attack arrowwood viburnum – the clearwing borer and the lesser viburnum borer. Adults are day-flying moths that resemble wasps. Larvae bore into inner bark and woody tissues, causing serious injury Don’t delay treatment once borers are detected
Eco-Friendly Borer Treatments
When dealing with borers on arrowwood viburnum, start with the most eco-friendly options first:
Encourage Beneficials – Natural predators like birds, beneficial insects, and nematodes help control borer populations. Avoid pesticides that would harm them.
Apply Neem Oil – The botanical insecticide neem oil smothers and repels borers. Use a spray bottle to coat trunk and branches about every 7-10 days.
Try Insecticidal Soap – Insecticidal soap kills larvae on contact while safely sparing most beneficials. Use a hand sprayer to thoroughly cover affected parts of the shrub.
Introduce Nematodes – Microscopic nematodes seek out and kill borer larvae in soil and under bark. Apply beneficial nematodes per package instructions.
Use Diatomaceous Earth – The sharp edges of this powdery compound pierce borer exoskeletons, killing them through dehydration. Dust it around the base.
Chemical Controls for Severe Infestations
For heavy borer infestations, biorational or organic chemical options may be needed as a last resort:
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Spinosad-based products – These target caterpillars while having low toxicity to wildlife and humans. Spray foliage thoroughly as larvae begin to emerge.
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Chlorantraniliprole (Acelepryn) – This anthranilic diamide insecticide offers long-lasting borer control with minimal environmental impact. Apply to trunks and lower branches where eggs are laid.
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Permethrin – Though more toxic to bees and aquatic life, permethrin is effective against clearwing moth borers. Use extreme caution and only treat tree trunks.
Always read and follow pesticide labels carefully to avoid plant damage or poisoning wildlife. Spot treat only infested shrubs when possible.
Preventing Infestations in the Future
An ounce of prevention is worth a pound of cure when dealing with viburnum borers. Here are some key tips for deterring future attacks:
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Maintain vigor through proper care like irrigation, fertilization, and pruning. Healthy shrubs resist borers better.
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Avoid wounding trunks and branches when working or mowing around viburnums. Damage attracts egg-laying moths.
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Clean up fallen branches and debris that offer borer breeding grounds. Destroy infested wood.
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Wrap lower trunks of susceptible varieties in burlap in early summer to interfere with egg-laying.
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Monitor weekly for signs of borer presence like holes, frass, or dying leaves. Act quickly at first signs.
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Select borer-resistant Viburnum varieties like arrowwood, Burkwood, and leatherleaf.
Protect Your Viburnum Investment
Taking action to get rid of borers on arrowwood viburnum at the first signs of trouble will help protect the health and longevity of this easygoing, ornamental shrub. When treatments are needed, start with gentle, organic options before considering chemical controls. Diligence in inspection and prevention will also deter future infestations of these destructive pests. Your efforts will allow you to continue enjoying graceful arrowwood viburnum as an elegant focal point in your landscape.
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Treating Thrips on Viburnum
Horticultural oils, soaps, and insecticides can all be used to treat thrips. When spraying, be sure to target the thrips directly. Most chemicals will be ineffective unless the thrips are thoroughly coated with the spray. Multiple applications every 1-2 weeks will be needed to fully kill the thrips. Soil drenches, which are pesticides applied to the root zone, may also be effective.
Be persistent and check on your viburnums every few days to monitor for thrips. While these insects are small and hard to see, their characteristic flecking and striping of plant leaves will determine their presence. Since thrips will likely not kill your plant, treatment is not always necessary. Be wary of harming non-target insects such as pollinators and predators of thrips when using pesticides.
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Viburnums are popular shrubs that provide stunning flowers and colorful fruit in the landscape. Although viburnums are easy to care for, they are favored by several pests, including insects and mites. Many pests, such as aphids, mites, scale, and thrips, usually only cause cosmetic damage, while pests such as viburnum leaf beetles, borers, and root weevils can cause more serious damage. With regular monitoring and treatment, your viburnum will be healthy and pest-free.
Viburnum leaf beetles, Pyrrhalta viburni, are an invasive pest of viburnum, introduced from Europe. These insects feed entirely on viburnums, chewing holes into the leaves of these shrubs. The feeding damage from viburnum leaf beetles and larvae resembles the lacy patterns left by Japanese beetles. Viburnums can be entirely defoliated by the end of the growing season. If continuous infestations occur in subsequent years, the viburnum may die.
In summer and fall, eggs are laid inside the twigs and branches of viburnums. Females chew rows of tiny holes on the underside of the branches, sealing them off with the chewed bark once the eggs are deposited. The eggs overwinter, hatching in late spring. The caterpillar-like larvae are less than 1/2-inch long with black dashes lined along their yellow-to-brown bodies. By mid-summer, the larvae finish pupating and emerge as adults, which look like small, brown and yellow beetles.
How To Treat Tree Borers.
FAQ
How do you treat viburnum borer?
How do you get rid of viburnum leaf beetles?
How to get rid of borers?
How do you get rid of tree borers naturally?
What causes borer damage on viburnum plants?
Borer damage on viburnums consists of plant dieback and general decline. You may see small holes on the base of the plants where the adults emerged. It’s not unusual for the plant to die as a result of its injuries. Stressed and damaged viburnum shrubs attract these borers.
Are Viburnum borers dangerous?
Viburnum borers cause serious damage to shrubs in the viburnum family. Learn to identify these insect pests and eliminate them from the landscape with the viburnum borer treatment tips in this article. So, what are viburnum borers? Viburnum borers are day-flying moths that look a lot like wasps.
Should arrowwood Viburnum be pruned?
Arrowwood viburnum shrubs don’t need extensive pruning. Right after the plant is done flowering, prune any stems necessary to maintain the shrub’s shape. Avoid taking off more than a third of the shrub’s overall size. Remove any dead, damaged, or diseased portions of the shrub whenever you spot them.
How do you know if a Viburnum has borer damage?
You’ll probably notice the damage to your shrubs before you notice the ordinary looking moths. Borer damage on viburnums consists of plant dieback and general decline. You may see small holes on the base of the plants where the adults emerged. It’s not unusual for the plant to die as a result of its injuries.