If you want to get rid of it, you have to understand the box tree moth. Here you will find everything you need to recognize and fight the voracious butterfly caterpillars.
You have noticed discolored leaves, dead branches, white webs and caterpillars on your boxwood (Buxus) - or noticed these symptoms in the neighborhood? It may be an infestation with the notorious box tree moth (Cydalima perspectalis). Now it's time to get information and act quickly to minimize damage to your shrubs.
The box tree moth is an invasive species native to East Asia. It was introduced to Central Europe a few years ago and specializes in our boxwood, which in many areas leads to complete defoliation. This overview article provides you with brief information on when the box tree moth occurs during the course of the year, how you can recognize and control it and what influence the time has on the success of control.
Box tree moth: Occurrence over the course of the year
The problem with the box tree moth is that it leads a rather hidden existence. The moths are nocturnal, so the eggs are laid unnoticed - as long as you not use a suitable pheromone trap. With a pheromone trap like the Plantura borer trap, you can detect an infestation at an early stage. Directly below this paragraph you can see a table showing the development of the moth over the course of the year. Unfortunately, this is not a generally valid representation, because the speed of larval development depends, among other things, on temperature. Even a very mild or very harsh spring can cause a delay of a few weeks. Unfortunately, observing the flight of moths with traps and regularly checking the bushes between March and September is the only reliable way to notice an incipient infestation in good time.
| month | April | May | June | July | August | September |
|---|---|---|---|---|---|---|
| Development State | Caterpillars (overwintered) | Cocoons | Moths, Eggs | Eggs, Caterpillars | Cocoons, moths | Moths, Eggs, Caterpillars |
| Generation | Generation previous year | Generation 1 | Generation 2 | |||
Recognizing box tree moths
Fortunately, detection is possible long before yellow and dead shoots appear in the bush: the yellowish borer eggs are located in the outer areas of the box tree, in densely packed "egg mirrors". Larvae that are only a few millimeters in size hatch from them. They are rather light and green-yellow in color and have a typical black head capsule. Immediately after hatching, they make their way into the protected interior of the bush to hide in webs and scrape at the poisonous boxwood leaves. When they have grown a little larger and have molted several times, the color of the caterpillars of the box tree moth changes somewhat to dark and the characteristic black and white markings appear. Now they leave the inside of the boxwood and go back to the outside areas. Finally, after 6 larval stages, the pupation follows, also hidden in webs. The resulting small butterfly is usually brightly colored. He cares for the next generation of voracious caterpillars. We have prepared detailed, illustrated articles for you that describe the moth eggs, the associated caterpillars and the moths of the box tree moth. You can find out more about recognizing the moth in this special article. If, based on this description, you suspect another disease in your boxwood, you can find out more about other diseases of Buxus .
Recognizing box tree moth summary:
- Severe infestations can lead to the death of smaller or larger branches.
- An infestation can be recognized much earlier by webs and caterpillars that are a maximum of 5 cm long. The caterpillars are green-yellow, later with black-and-white markings and white bristles. The black head capsule is typical.
- The eggs are yellowish and are laid in groups in the outer areas under the leaf.
- The approximately 4.5 cm wide moths are not always the same colour, they are mostly light with black wing edges.
Fight box tree moths
If you recognized the infestation early or if it is weak, we recommend reading this special article on effective home remedies for combating the box tree moth. He describes working measures - such as the high-pressure cleaner - and less effective approaches -like baking powder. But if you are already standing in front of a dying box tree full of caterpillars - you don't have to start collecting them anymore. You can now decide: Do you look for alternatives for the box tree or do you try to fight the moth moth? You can find out here how combating the borer works in general. Anyone who has no interest in fighting the caterpillars with poison will find biological ways here that achieve good results without chemicals. The use of nematodes, neem oil, and preparations containing Bacillus thuringiensisare far more promising than the environmental credentials of these products would suggest. Although conventional means are often effective, the reduction of important beneficial insects in the garden often creates new problems with pests. We recommend always carefully comparing the package insert with the official requirements before buying a crop protection product.
Tip: Don't be afraid to collect and dispose of the boxwood moths. The caterpillars are not poisonous on skin contact. But you shouldn't eat them - and wash your hands better after contact. Inside, the little animals house several toxic compounds that they have absorbed from the boxwood, which is also poisonous. In our article “Are box tree moths poisonous?” learn more about the toxicity of the borer.
When is the best time to fight the moth?
The following applies to the moth: The choice of time determines the success of the fight. Anyone who applies a spray against the caterpillars, although they are still well wrapped up in their leaf webs, should not expect a reduction in the infestation. The same applies if the borers are still eggs or already cocoons. So when does it make sense to inject remedies against the box tree moth or to use something else? This article will guide you at the right time to fight the box tree moth.
Box tree moth biologically with XenTari® Fight
Anyone looking for an effective, simple and yet environmentally friendly control method should use our Plantura Zünslerfrei XenTari®. Our Plantura Zünslerfrei XenTari® is used in organic farming and in professionally tended ornamental and vegetable gardens because it has no effect on beneficial insects or even humans. It works - unlike other sprays available - only against the caterpillars ofcertain butterflies like the moth.
The contained active ingredient is a surviving spores of a specialized bacterium, the Bacillus thuringiensis. If these are applied to the leaf of the infested plant, they can be picked up by caterpillars when they eat. In the intestine, the bacteria release a toxin that not only leads to an immediate stop in feeding, but also causes the caterpillars to perish after a maximum of five days. Because of the high specificity, safety for the user and good effectiveness, we recommend using this biological spray.
Tip: You can also use our Plantura Zünslerfrei XenTari® to free pome fruit trees and cabbage plants from caterpillars - the large and small cabbage white butterfly can help here fought with the remedy.
The boxwood moth is not the only problem boxwood owners have to contend with. Here you can find out everything about the boxwood fungus.