Eliminating Thrips in Arrowwood Viburnum Shrubs

Arrowwood viburnum (Viburnum dentatum) is a tough, adaptable shrub that adds beauty to landscapes with its white spring blooms, shiny foliage, and showy blue berries in fall. However, these ornamental shrubs are vulnerable to infestations of tiny, winged insects called thrips that can stunt growth, disfigure leaves and flowers, and reduce the plant’s health. Getting rid of thrips in arrowwood viburnum requires persistence and an integrated approach, but is worthwhile to protect the plant. In this article, we’ll explore effective strategies for eliminating thrips in arrowwood viburnum shrubs.

Understanding Thrips and Their Damage

Thrips are slender, dark-colored insects less than 1/25th of an inch long. Two common species that attack arrowwood viburnum are western flower thrips and eastern flower thrips. Thrips pierce plant cells and suck out the contents, leaving behind white or silver streaks and patches on leaves, flowers, and buds. Heavily infested plants become weakened and disfigured. Thrips also transmit harmful plant viruses.

In arrowwood viburnum look for the following signs of thrips damage

• Distorted, curled leaves with dried edges
• Silvery-white streaks or patches on foliage
• Discolored dead spots on leaves and flowers
• Stunted growth of new leaves and shoots

Thrips mainly hide inside tightly closed buds and other hidden crevices during their lifecycle. This makes them difficult to control So taking preventive and integrated measures is key for effective thrips management

Preventing Thrips Before They Become a Problem

Stopping an infestation before it starts is the best approach. Here are some tips:

• Select thrips-resistant arrowwood cultivars like ‘Blue Muffin’ or ‘Raspberry Tart’

• Avoid planting arrowwood viburnum near infested plants like roses or vegetables.

• Remove weeds like clover and dandelions that attract thrips.

• Apply diatomaceous earth as a natural deterrent around the base of plants.

• Use reflective mulch to confuse and repel the insects.

• Frequently monitor plants during warmer months looking for signs of infestation.

Taking prevention seriously makes a significant difference in avoiding major thrips issues later on. But if thrips still occur, take action right away before they multiply.

Safe, Organic Methods to Control Thrips

If a minor thrips infestation occurs, start with gentle, non-toxic control methods:

• Knock thrips off with a strong spray of water from the hose. Focus on leaf undersides.

• Apply neem oil, insecticidal soap, or horticultural oil sprays per label instructions to smother thrips.

• Dust small infestations with food-grade diatomaceous earth to abrade insect bodies. Avoid breathing it in.

• Release predatory insects like minute pirate bugs, lacewings, and lady beetles to consume thrips naturally.

• Set out yellow or blue sticky traps near plants to catch adult thrips flying by.

• Remove and bag up heavily damaged leaves and buds to eliminate thrips hiding inside.

These organic approaches often successfully tackle minor infestations if used persistently. But severe thrips issues may need stronger treatment.

Insecticides to Control Heavy Thrips Infestations

For large-scale thrips infestations, insecticides are faster and more effective:

• Azadirachtin – Derived from the neem tree, commercial azadirachtin products disrupt thrips’ molting process.

• Insecticidal soaps – Soaps containing potassium salts of fatty acids dissolve thrips’ exoskeletons on contact.

• Pyrethrins – These chemicals derived from chrysanthemum flowers work quickly but have limited residual action.

• Spinosad – This bacterium-based insecticide is especially effective against thrips but must be applied carefully to avoid harming bees.

• Acephate – A strong systemic insecticide, acephate is taken up by plants’ vascular systems to poison thrips ingesting plant material.

When using any chemical control, properly identify the thrips species first to ensure your product will be effective. Follow all label instructions carefully.

Ongoing Thrips Prevention and Monitoring

To avoid repeated bouts with thrips, keep up prevention efforts even after the infestation clears:

• Continue releasing beneficial predatory insects to naturally control thrips.

• Apply a layer of fresh diatomaceous earth periodically as an abrasive deterrent.

• Routinely inspect arrowwood viburnums, especially under leaves and in buds where thrips hide.

• Monitor for signs of damage and treat quickly if thrips return.

Staying vigilant will allow you to get ahead of any potential re-infestations before they spread. With persistence and an integrated pest management approach, you can successfully banish thrips from your arrowwood viburnum shrubs long-term.