summary
- The box tree moth caterpillar can be destroyed by a biological insecticide
- How to recognize and identify the box tree moth?
- How to treat and combat box tree moth
- To preserve the bees, the strategy is to attack the caterpillar of the pyralid moth
- The treatment will be more effective if it is done early in the season.
- Another natural insecticide: Diatomaceous earth
- Manual disposal
The box tree moth caterpillar can be destroyed by a biological insecticide
Solabiol, organic insecticide Bacillus Thurengiensis
The box tree moth appeared in France a few years ago and was declared an "invasive species" in 2008 by the EPPO (European and Mediterranean Plant Protection Organization). It was first noticed in Alsace, Poitou and Île-de-France. And since 2014, it has invaded all of France and Switzerland.
If we do not want to see the disappearance of box trees in a few years, it is absolutely necessary to fight very vigorously against this moth and its gluttonous caterpillar.
How to recognize and identify the box tree moth?
- The butterfly : large, 3 to 5 cm, its white wings are bordered with a brown edge with purplish reflections. It is nocturnal, so unless it is disturbed, it does not appear during the day.
- The caterpillar : also large, 4 to 5 cm, striped lengthwise in light green, dark green and black. Luckily it is not stinging, it has chosen a different method to repel its predators: by feeding on boxwood, it concentrates in itself the many active ingredients contained in this plant to the point of becoming toxic for birds. It therefore has no predator.
- Webs and cocoons : if your box tree looks disgusting, if its leaves are woven and twisted into a kind of spider web dotted with green balls of excrement, it is because it is colonized by the box tree moth.
- The trap : at the beginning of the infestation, you can't see anything. The moth is nocturnal, and the first caterpillars settle in the heart of the bush. When you see caterpillars on the outer leaves or you notice that some branches are dying, the moth is already well established and the damage is already significant.
How to treat and combat box tree moth
The use of very powerful and hyper-effective products is tempting, I am thinking of pyrethroids. But as I specify in the article of my blog devoted to pyrethrum, pyrethrin and pyrethroids , I absolutely advise you not to use these active ingredients outside the houses . These products are too effective and act by contact, they would destroy as much the bees, the butterflies, the ladybugs as the moth that you wish to eliminate.
To preserve the bees, the strategy is to attack the moth caterpillar.
Unlike bees and all foraging and pollinating insects, the box tree moth caterpillar devours the leaves of the box tree. By poisoning the foliage with bacteria, the biological insecticide Solabiol Bacillus Thurengiensis transforms your box tree into a death trap for the caterpillars, which will die in two to three days.
Authorized in organic farming , this insecticide acts by ingestion of treated plants. Unscrupulous and gluttonous insects will ingest Bacillus Thuringiensis (BT) which will develop crystals made up of several proteins and which will destroy their intestinal cells. To protect bees and pollinators in general, these insects must not be in contact with the product in liquid form, so it is necessary to treat in the evening when these insects are at rest. Under these conditions, bees that do not eat the plants will not be worried.
The treatment will be more effective if it is done early in the season.
The box tree moth has three reproductive cycles each year : in spring, in June-July and then in September.
Ideally, treat in dry weather when the temperature is above 15° so that the caterpillars are fully active and at the end of the day when the bees have finished foraging. Do not spray in the presence of bees to prevent them from taking this mist for dew and absorbing it, which would be fatal for them . Also ideally, it would be good to treat before the caterpillars appear.
Please note that Bacillus Thuringiensis (BT) is a plant protection product. It is important to respect the prescribed doses and to carefully read the instructions and precautions for use on the packaging.
Some tips:
- Check your box trees regularly by inspecting them right down to the heart of the foliage. You will be alerted if you see white and brown butterflies 3 to 5 cm long emerging from them, if you see woven webs forming a kind of cocoon with the leaves dotted with balls of green droppings, and of course if you find insatiable caterpillars.
- The greatest caution should be exercised when purchasing new boxwood .
- This insect, which has no natural predator, appeared very recently in Europe, in 2008. We are aware of the extent to which its ravages are significant and risk destroying all the box trees in just a few years. It is therefore necessary for each of us who are confronted with this pest to do everything possible to kill as many box tree caterpillars as possible.
Another natural insecticide: Diatomaceous earth
You can also sprinkle your boxwood with diatomaceous earth . It is an all-natural insecticide and does not cause any habituation in insects.
Manual disposal
This technique has the advantage of not spreading any product in nature. Since the box tree moth caterpillars are not irritating, you can remove them by hand, especially in winter when they are found nestled in the form of cocoons in the heart of boxwood clumps. The caterpillars thus "picked" must be destroyed by burning or by drowning them in a bucket of water.
You are dealing with a tough opponent, you are his only predator, so the fight will be over time.
