Box and birds, 1 year later…

in Research 17 November 2020

“Not pesticide boxwood moth, but flea and tick tapes of pets are killers, says research.”

This remarkable title was placed above an article by VRT Nieuws exactly 1 year ago. After 2 – 3 years of unjustified accusations against garden owners fighting the box caterpillar, it became painfully clear that the active substances found in dead birds did not originate from caterpillar drugs.

Three investigations were carried out in response to fatalities: 2 studies in the Netherlands and 1 in Belgium. After extensive analysis, it was found that the active substances found in dead birds could not have been derived from caterpillar drugs. The claim that box caterpillar control was the cause of these fatalities was invalidated! What was found, however, were the active substances used in so-called home remedies such as ant lure boxes, fly and mosquito control and flea collars for dogs and cats. In addition, other research has shown that some fat balls for birds contain pesticides.

picture: VRT Nieuws

The research and technical analysis can be read in full here:

Fat balls analysis: December 2019:VELT

picture: Velt

And then it became silent…. except for a single message ….

This contrasts sharply with the dozens of prominent messages in recent years, each with a direct attack on boxwood with very serious consequences for the growers. Fortunately, research and common sense have shown that the truth is always much more complex than the title of some articles.

During consultations of a group of box tree growers with a nature association in 2018, this problem was nevertheless mentioned, but apparently other interests played a part. In their view, boxwood was just a vulgar garden plant and had little added value for biodiversity. Birds would not breed in a dense Boxwood plant and boxwood would not be native to Belgium. Caterpillar control, including biological control, was not considered and advice was given to remove the plant. Boxwood was condemned by many and pulled out en masse and at times it looked like an environmental disaster had happened in some container parks. The consequences are now painfully obvious. Many front gardens have been transformed into barren plains with pavement.

These lies were all refuted. Boxwood is indeed native to Belgium and part of the biologically very rich limestone grasslands with the largest number of butterflies, dragonflies and orchids. Moreover, the flowers of Buxus are very important for both wild and common bees. This evergreen plant offers protection to a large number of animals. Birds breed en masse in these dense bush that protects their nests. Research in France showed that around 300 animal species depend directly on the, admittedly wild, boxwood biotope. Boxwood grows well on all types of soil and also on the often less fertile soil we find in our front gardens.

The box moth is an invasive moth from Asia that has a preference for our European Buxus sempervirens. All other invasive exotic species are fought and/or kept under control in accordance with our exotic species policy of both the government and nature associations. Why a frontal attack on the box moth was chosen instead of on the invasive exotic species is completely unclear to me.

Garden owners who had not given up their boxwood, notice today that their plants look more beautiful than ever, despite the dry summers we had in recent years. With proper care, and that includes watering and fertilization, Boxwood is still an easy plant to grow. The pest pressure of box moth is fortunately on its way back, and control is perfectly possible with organic plant protection, which is also used in the organic cultivation of fruit and vegetables.

Biodiversity in Buxus:
Good news for people who want more biodiversity.

There are also species of boxwood that appear to be less susceptible to infestation by the box caterpillar, by analogy with species that are less susceptible to fungal disease. The latest development is our Betterbuxus® hybrids that were developed in collaboration with ILVO, Institute for Agricultural and Fisheries Research. These hybrids are resistant to fungal diseases in Boxwood, developed in Flanders on the basis of a very extensive collection of species and cultivars. There is no longer any reason to ban boxwood from your garden! Initially launched in large historic gardens in Europe, they are now also available exclusively through our “Boxwood Ambassadors”.
You can find all the info on

Author Didier Hermans
Box researcher, box specialist