The boxwood borer is a persistent pest that threatens the boxwood. Its caterpillars eat the leaves and can cause a lot of damage in a short period of time. Read here what helps against the box tree borer.

They are green, black, well-camouflaged caterpillars that transform into delicate white butterflies after pupating. That’s nice in itself, but boxwood moths are a nuisance for garden owners.

As the name suggests, the pests attack boxwoods and can destroy them completely – if the infestation is not detected in time. The best protection for your trees is therefore precaution.

Once the boxwood borer is there, there is an effective and quick way to stop the infestation and prevent the boxwood from dying: Bacillus thuringiensis, a biological insecticide that causes the caterpillars to die within a few days.

At the same time, the bacterium does not harm bees or other beneficial insects. It is also recommended by the Federal Environment Agency for environmentally friendly control of the box tree borer. 

It is important to follow the respective product instructions exactly. It is best to spray the product generously onto your boxwood trees and make sure that you also wet the inside of the tree with the product. In the following table we show you popular products that are specifically designed for the boxwood moth.

In this country, there are about two to three generations per year between March and October. During this period, you should therefore regularly inspect your box trees for signs of infestation.

The infestation cannot be recognized immediately. First, the female moths lay tiny eggs (up to 150 per female) on the underside of preferred young leaves. After about three days, the larvae hatch and begin to eat, preferably the leaves and bark of the box trees. Once this stage is reached and the larva develops into a caterpillar, there are clear signs of an infestation:

There is no 100% protection against infestation. But you can at least take preventative measures on a small scale. Fine-meshed plant protection nets are best suited here.

Since the boxwood is a poisonous plant and the caterpillars absorb the alkaloids when they eat the tree, there are not many predators. However, since the East Asian pest was introduced, some local birds such as great tits and sparrows have adapted to eating it. Other predators include hornets, wasps, bats and predatory spiders. So if you create a good habitat for the predators, you can also curb the spread.

The original for this article “Threatens the garden – this now helps against the box tree borer” comes from