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Viburnums are a diverse group of flowering shrubs that are very popular in the garden. Unfortunately, they’re often preyed upon by a wide range of pests. Keep reading to learn more about the insects affecting viburnums and how to go about controlling viburnum insect pests.
Arrowwood viburnum shrubs are prized for their showy spring blooms and fall berries. But spider mite infestations can threaten the health and appearance of these popular landscape plants. Getting rid of spider mites in arrowwood viburnums takes persistence and an integrated approach. But with prompt action, you can protect the beauty and vigor of your viburnums.
What Are Spider Mites?
Spider mites are tiny, eight-legged pests closely related to spiders. The most common species is the two-spotted spider mite, which is only 1/50 inch long. These pests have needle-like mouthparts that pierce plant cells. They suck out the contents, causing stippling, discoloration, and eventual leaf drop.
Webbing on plants is a telltale sign of spider mites. They produce fine silk threads to help them move around and lay eggs. Outbreaks often start when weather warms in spring. High populations can develop rapidly in hot, dry conditions.
How to Identify Spider Mite Damage
Watch for these symptoms of spider mite infestations on arrowwood viburnum
- Yellow stippling or speckling on upper leaf surfaces
- Fine webbing on branches
- Browning and dropping of leaves
- Tiny dark dots moving on webs when disturbed
- Overall lackluster appearance
Shake a branch over white paper to help detect the spider mites themselves. They will look like tiny specks crawling on the paper. Inspect the undersides of leaves closely using a magnifying glass where mites often congregate.
Natural Ways to Control Spider Mites
For light infestations, try these organic methods first to get rid of spider mites:
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Water spray Blast leaves and stems with a strong stream of water twice weekly to physically remove mites
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Neem oil This organic insecticide coats mites to suffocate them Apply neem oil spray every 1-2 weeks
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Insecticidal soap: Soap solutions disrupt mite membranes on contact. Spray leaves, especially undersides, every 5-7 days.
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Ladybugs: These voracious predators feast on spider mites. Release them near infested viburnums.
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Reflective mulch: The bright surface repels spider mites. Place 1-2 inches around viburnums.
These natural remedies work best when spider mite populations are low. Move quickly to curb early infestations before they escalate out of control.
Chemical Pesticides for Severe Spider Mite Problems
For heavy infestations, pesticides may be necessary to save severely damaged plants. Miticides target mites specifically, while systemic insecticides are absorbed by plants. However, these chemicals also kill beneficial insects. Use selective ingredients like:
- Abamectin
- Fenpyroximate
- Spiromesifen
- Spirotetramat
Follow label directions carefully. Repeat applications may be needed. Combine chemical control with natural methods like reflective mulch for most effective protection.
Preventing Spider Mites in Arrowwood Viburnums
Once spider mites are eliminated, take these steps to discourage reinfestations:
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Hose off viburnums weekly to remove mites and webs.
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Release predatory mites like Phytoseiulus persimilis that eat spider mites.
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Hang up yellow sticky traps to catch migrating spider mites.
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Avoid excess nitrogen fertilization that promotes mite-favored succulent growth.
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Prune and discard any highly infested branches and leaves.
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Space viburnums properly for good air circulation.
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Introduce beneficial insects like lady beetles and green lacewings.
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Mist viburnum foliage regularly to discourage mites.
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Apply horticultural oil or insecticidal soap preventively every 2-3 weeks as needed.
What to Do if Spider Mites Persist
Spider mites can be challenging to get rid of completely. Their rapid reproduction enables populations to quickly bounce back. If mites continue causing damage after treatment:
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Switch to a different miticide active ingredient than what was used before.
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Use plant-based miticides like neem oil in rotation with chemical options.
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Remove any weeds, debris, or infested plants that can harbor mites.
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Consider replacing susceptible viburnums with mite-resistant plant varieties.
With persistence and an integrated pest management plan, you can protect the beauty of your arrowwood viburnums. The key is taking quick action at the first signs of spider mites before they get out of control. Combining natural remedies, targeted miticides, and prevention will provide the most effective protection against these destructive pests.
Frequently Asked Questions about Controlling Spider Mites in Viburnums
Still have concerns about getting rid of spider mites in your arrowwood viburnums? Here are answers to some common questions:
Why do spider mites attack viburnums?
Spider mites thrive in hot, dry conditions. Viburnums stressed by drought or poor cultural practices are more vulnerable to infestations. Mites are also blown in from nearby infested plants.
How do you know if spider mites are gone after treatment?
Inspect viburnum leaves closely, especially the undersides. Look for any remaining webbing, stippling damage or live mites. Spider mites are difficult to eliminate fully. Continued monitoring and re-treatment are often needed.
Are spider mites harmful to humans?
No, spider mites do not bite humans or pets. They feed only on plant material. But chemicals used to kill mites can be toxic if misapplied. Always follow label safety directions.
What kills spider mites naturally outdoors?
Heavy rain and cold winter weather can reduce mite populations. Encouraging natural predatory insects like ladybugs, green lacewings and predatory mites also helps control them.
When should you treat viburnums for spider mites?
Treat viburnums for spider mites as soon as any webbing or speckling damage is spotted, before the infestation escalates. Early detection and treatment are key for the best control.
Controlling destructive spider mites is crucial to the health and appearance of arrowwood viburnums. By taking prompt, thorough action using integrated pest management strategies, you can protect the beauty of your landscape plants. Be vigilant in monitoring for early signs of infestations, and don’t hesitate to intervene at the first sign of damage before spider mite populations explode out of control.
Common Pests on Viburnum
Here are some of the most common viburnum pests and methods for viburnum pest control. Aphids – While they don’t cause much damage, aphids can cause curling in new growth. They can be gotten rid of with a steady stream of water from the hose, insecticidal soap, or horticultural oil. Thrips – Thrips can cause purple spots on leaves, curled and dropped leaves, and dropped, unopened flower buds. Try to prevent thrips by keeping weeds under the shrub to a minimum. Spray with insecticidal soap, if necessary, but be careful, as there are many beneficial insects that feed on thrips. You can also introduce beneficial insects such as lacewings, ladybugs, and predatory mites to the garden. Southern Red Spider Mites – The leaves turn gray/brown and drop when these red spider mites are present. Mites can be knocked off with a strong spray from the hose or treated with insecticidal soap. Scale – Armored scale cause leaf drop, discolored leaves, and stunted growth. Light infestations of scale bugs can be scraped off by hand, and heavier ones can be treated with insecticide. Other insects affecting viburnums include: Weevils – Weevils chew on the edges of leaves. While they’re not usually dangerous, the damage isn’t pretty. Spray the leaves and ground below the shrub with insecticidal spray to kill the adults. Repeat every two to three weeks to kill each generation. Asiatic Garden Beetles – Flowers, leaves, and new growth is skeletonized when Asiatic garden beetles are around. Common types include the Japanese beetle. Remove adults by hand and introduce nematodes to the soil. Dogwood Twig Borers – Dogwood borers will dig out holes in the stems, leaving sawdust behind. Crush eggs in early summer. Stick a wire into every hole you find to kill the borer inside. Viburnum Leaf Beetles – Plant resistant viburnum varieties to avoid viburnum leaf beetles. Prune away egg-infested branches during the winter. Introduce lacewings as beneficial insects.