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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 a popular choice for many gardens and landscapes. Their pretty white flowers in spring, attractive foliage, and bright red berries in fall give them year-round appeal However, these shrubs can fall victim to pesky crusader bugs that can quickly damage the plant’s health and appearance In this comprehensive guide, I’ll explain what crusader bugs are, the damage they cause, and most importantly – how to get rid of them on your arrowwood viburnum shrubs.
What Are Crusader Bugs?
Crusader bugs (Mictis profana) are a type of sap-sucking insect that feeds on a variety of plants including viburnums. They are true bugs in the order Hemiptera and are characterized by their elongate shield-shaped bodies that are typically black or brown in color.
Adult crusader bugs are approximately 1⁄4 inch long. Their name comes from the row of spines or hairs along their back that resemble a knight’s armor. Nymphs are smaller and wingless.
Both adults and nymphs use their piercing-sucking mouthparts to feed on plant sap They insert their needle-like stylets into the plant tissue and suck out the sap This damages the plant and can spread disease,
How Do Crusader Bugs Damage Arrowwood Viburnum?
When crusader bugs feed on arrowwood viburnum, they target the leaves and young shoots. Their feeding causes yellow, brown, or black spots on the foliage. If left untreated, they can skeletonize leaves and cause extensive defoliation.
Repeated attacks over multiple seasons can significantly stunt the plant’s growth. It prevents the shrub from developing properly and producing flowers and berries. Severe infestations can even kill branches or entire plants.
In addition to the physical damage, crusader bugs excrete sticky honeydew as they feed. This sugary substance coats the leaves and promotes the growth of sooty mold fungus. The black mold covers the leaf surfaces and blocks sunlight from reaching the plant tissues.
How To Get Rid of Crusader Bugs on Arrowwood Viburnum
If you suspect crusader bugs are attacking your arrowwood viburnum, take action right away to limit the damage. Here are the most effective methods to eliminate these pests:
Encourage Natural Predators
Lady beetles, lacewings, assassin bugs, and birds prey on crusader bugs. Attract these beneficial insects by planting nectar-rich flowers like daisies, asters, and goldenrod nearby. Avoid using broad-spectrum insecticides that kill the good bugs as well as the bad.
Manual Removal
For light infestations, handpicking and dropping the bugs into soapy water is effective. Be sure to check the undersides of leaves where they often hide. Wear gloves to avoid irritation from their defensive secretions.
Apply Horticultural Oils
Coating the plants with lightweight horticultural oils smothers crusader bug nymphs and eggs. It also deter adults from feeding and laying eggs. Spray both sides of leaves and stems every 10-14 days.
Use Insecticidal Soaps
Insecticidal soap sprays directly kill crusader bugs on contact while sparing most beneficials. For optimal results, thoroughly cover the foliage, especially new growth. Reapply every 5-7 days as needed.
Employ Systemic Insecticides
Systemic insecticides like imidacloprid are absorbed by the roots and make the whole plant toxic to sap-sucking insects. Apply as a soil drench or granules around the root zone in early spring. Protect pollinators by not applying during bloom time.
Apply Neem Oil
Extracted from the seeds of the neem tree, neem oil disrupts the crusader bug life cycle and prevents larvae from maturing. Use a diluted neem oil foliar spray every 7-14 days to deter feeding and egg-laying in adults.
Release Beneficial Nematodes
Parasitic nematodes seek out and kill crusader bug larvae in the soil. Apply them during mild, moist conditions in early spring and water the area thoroughly after release. Reapply every 6-8 weeks as needed.
Employ Physical Barriers
Wrap tree trunks with sticky barrier bands to trap migrating nymphs and keep them off your viburnum’s leaves. Prune any heavily infested branches and destroy them.
How To Prevent Future Crusader Bug Infestations
Once you knock down an existing crusader bug population, take these steps to prevent reinfestations:
- Monitor plants frequently for early detection
- Promote beneficial insect habitat in your landscape
- Avoid excess fertilization that encourages soft, sappy growth
- Keep plants healthy with proper watering, pruning, etc.
- Clean up and destroy fallen leaves/debris where bugs may overwinter
With vigilance and integrated pest management, you can protect your arrowwood viburnums from crusader bug damage. Don’t let these sneaky sap-suckers ruin the ornamental beauty of this classic landscape plant. Implement a combination of organic and conventional control methods for an effective, environmentally-friendly solution.
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.
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FAQ
How do you treat viburnum pests?
How do you treat viburnum mites?
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Pest
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Treatment
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Spider Mites
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Avoid overcrowding, introduce natural predators like ladybugs, lacewings, and predatory mites. Use horticultural oil or insecticidal soap.
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Thrips
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Insecticidal soaps or pyrethroid-based insecticides can be effective. Multiple treatments may be required.
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What is the pest in the Arrowwood viburnum?
What is the best insecticide for viburnum beetles?
Are arrowwood viburnum shrubs poisonous?
Arrowwood viburnum shrubs don’t have serious issues with most pests or diseases. However, they might be bothered by the viburnum leaf beetle ( Pyrrhalta viburni ). This beetle has become a major problem for viburnum shrubs in Europe and North America. Both the adult beetles and their larvae eat the leaves of the bushes.
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.
Why should you plant arrowwood Viburnum?
If you need one more reason to plant this easy-going shrub, here it is: Arrowwood Viburnum is a host plant for Spring Azure butterflies. A host plant is a specific plant that a bug or butterfly lays its eggs on. Without host plants like Arrowwood Viburnum, we would not have Spring Azure butterflies.
Is arrowwood Viburnum indestructible?
Arrowwood Viburnum is a great native shrub that some landscapers call indestructible since it thrives with minimal care. Ideas for planting include: Arrowwood Viburnum is a perfect plant for beginner gardeners. It thrives in a wide range of sunlight—from full sun to part shade. Once you’ve found a spot to plant one…