Insects can be a major problem for trees. Some insects eat or suck leaves and some eat wood tissue. Many insects also introduce fungi into trees. Quite often, insects attack unhealthy trees when their immune system is low. However, some species of insects attack healthy trees of specific species, while termites will attack any type of tree at any time.

Examples of Trees Needing Treatment:

Ficus trees, fruit trees, palms, pine trees, exotic species, and unhealthy trees

Locations Where Treatment is Recommended for Protection:

Properties near slopes with trees, next to country parks and other unmanaged forests

When Are Insects Active in Hong Kong?

We reference the seasonal patterns of specific insects for specific tree species and carry out treatments to prevent infestation before it starts. This is the most effective strategy for controlling insect populations and reducing impact on the health of trees and vegetation.

The active insect season varies each year based upon the weather conditions. If spring starts early, insects also tend to start early. The best time for treatment is 1-2 months before spring. The second best time for treatment is immediately.

If treatment cannot be done during the recommended period between December and February, the second best time for treatment is immediately.

Some Specific Insect Problems That Require Treatment

Red Palm Weevil Attacking Palm Trees

The red palm weevil feeds on the vascular tissue of the new palm fronds. If not treated early, it can kill palm trees. Signs of the palm weevil are when new palm fronds turn brown before old palm fronds. Preventative treatment is recommended before problems start.

When mature, this beetle quickly moves to adjacent trees to continue feeding.

Caterpillars Eating Ficus Leaves

If not treated, caterpillars such as the Phauda flammans species will eat ALL of the leaves of Ficus trees. This can happen suddenly and without warning. The best time for treatment is right now before they become active in spring season.

We recommend our trunk injection method and potentially soil injection method as needed.

There are a few types of caterpillars to watch out for including the Phauda flammans and also the Perina nuda species.

Click here to read the Phauda flammans Diagnostic and Treatment Guide

Boring Insects on Tree Trunks

The Asian Longhorned Beetle digs into tree trunks where it feeds on wood tissue. This is very damaging for tree health. In addition, these beetles introduce fungi into trees which they feed on during early stages. This fungi can be a second problem if treatment is not done early.

After the beetle matures, it quickly flies to adjacent trees and continues feeding and reproduction.

Termites Inside Trees

Underground termites such as the Formosan termite attack trees from below ground up into the tree trunk. They feed on wood 24 hours a day, every day and a mature colony includes millions of termites that spread to other trees and wood structures. Trees are often the first place they attack on a property.

Termites also bring fungi with them into trees which they feed on during development.

These underground termites feed on living and dead wood tissue. This means that even healthy trees are in danger.

Pine Wilt Nematode in Pine Trees

Pine wilt is a fatal disease of pine trees caused by the nematode Bursaphelenchus xylophilus. The disease is vectored by pine sawyer beetles (Monochamus sp.) as they feed on the bark and foliage. Trees can die within weeks of the initial infection, leaving brown, dead needles still attached to the branches.

Insects Introduce Fungi into Trees

Many types of boring insects, such as beetles and termites, introduce fungi into trees. After eggs hatch inside the tree and beetle larvae not only feed on wood tissue but also fungi that was left behind by the adult beetle. After the insects develop from larvae to adult, they carry the fungi on their exoskeletons in search of a new host tree. This continues the cycle as the adult insects introduce fungi into new trees.

When we treat for infestation by boring insects such as beetles and termites, we also consider treatment for fungal disease as these commonly occur together. If not treated early, this can lead to escalated tree health decline.

We Have Solutions for Insect Problems

Treatment Methods & Equipment

Trunk Injection

The treatment is injected straight into the tree’s trunk and the solution is taken up by the tree’s natural water and nutrient pathways and out to every part of the tree canopy.

This method is especially useful for trees where soil is inaccessible due to paved concrete around the trunk, for example, wall trees, trees growing in sidewalks, or trees with root-attacking fungi.

Soil Injection

We utilise the soil injection method for various types of treatment applications for health improvement or fungi and insects prevention. This method of application is highly effective for introducing beneficial systemic treatments to tree roots for uptake into the tree. We are even able to treat trees that are almost entirely surrounded by concrete.

Bark & Foliar Spray

We use a special spray head that minimizes spray drift and maximises treatment coverage. This method of application is sometimes necessary depending on the type of issue we are treating. For example, certain types of termites primarily feed on the outer surface of trees.

Timing of Treatments

The various methods of treatment have varied periods of effectiveness. For example, foliar spray application may have immediate effects, but the effects don’t last as long. Soil injection or soil drench applications for systemic treatment may take a few weeks to go up into the tree, but their effects generally last for 1 year or more. Trunk injections, however, can produce rapid results and remain active for long periods of time.

The recommended treatment method is determined based on the season, tree species, tree health condition, and the targeted issue.

We Have Treatment Strategies for These Insects

Black Vine Weevil Larvae
Bronze Birch Borer
Gall Midge
Moth Larvae
Elm Leaf Beetle
Flatheaded Borer
Japanese Beetle
Pine Tip Moth Larvae
Plant Bug
Plant Hopper
Psyllids (including Lerp Psyllid)
Roundheaded Borers
Asian Longhorned Beetle
Citrus Longhorned Beetle

Cottonwood Longhorned Borer
Eucalyptus Longhorned Borer
Royal Palm Bugs
Sawfly Larvae
Scale Insects
European Red Mite
Twospotted Spider Mite
Camine Spider Mite
Southern Red Mite
Spruce Spider Mite
Tarsoneimid Mite
Cyclamen Mite
Broad Mite
Eriophyid Mite
Rust and Bud Mite
Eastern Tent Caterpillar
Fall Webworm
White pine weevil
Pine wilt nematode