Caterpillars on the box tree immediately ring the alarm bells. It could be the dreaded box tree moth. It is therefore important to reliably identify the caterpillars of the pest and to combat them accordingly.

Identify caterpillars on boxwood

Apart from the notorious box tree moth (Cydalima perspectalis), other moth caterpillars can also get lost in the box tree. For example, looking for a winter hiding place or a place where they can pupate. However, these larvae are completely harmless to the buchs itself. It is all the more important to reliably identify box tree moth caterpillars.

features

  • fully grown to 5 cm long
  • yellow to dark green in the basic colour
  • black and white drawing on the back
  • white haired
  • black head

Look for moths and pupae

In addition to the caterpillars, the moths and pupae of the box tree moth can also be found on the box tree, and there are also webs in the foliage. These can resemble cobwebs or consist of leaves spun together.

recognize dolls

  • up to 5 cm long
  • can be found inside the book
  • first yellowish later darkening
  • in poems Spinning

recognize moths

  • Wingspan up to 4 cm
  • Basic color white
  • dark brown frame around the wings

While the moths are around the boxwood, the caterpillars and pupae are inside the plant. There can be several generations per year. The last generation of borer moths overwinter in cocoons directly in the box.

Note: A winter check on box trees can be useful to decimate the first moth generation in the new year.

damage picture

The moths themselves are harmless to the plant, but the larvae can literally eat the box bare. Since they are initially inside the plant, they are often only noticed when the damage is already very great. It is therefore important to pay close attention to boxwood. These are the signs that should set your alarm bells ringing:

  • eaten leaves
  • Spun on the box
  • brown, dried leaves
  • droppings around the plant

Fight caterpillars on boxwood

Since the box tree moth causes great damage, it is necessary to fight it in a timely and effective manner. Unfortunately, in most cases this is not enough. In order to increase the success of the control, it is advisable to check the box trees regularly from early spring, around March, as the borer caterpillars can then already be active. As soon as the first suspicion arises, countermeasures must be initiated.

First aid

The most important home remedy to start with is collecting the caterpillars on the boxwood by hand.

  • Be sure to dispose of the larvae in the household waste
  • very effective with weak infestation
  • however, this is hardly practical for large box trees
  • simultaneous pruning of heavily infested areas helpful
  • Also put clippings in the household waste

A more effective home remedy is hosing down with a pressure washer. To do this, lay out a light-colored tarpaulin on the ground around the plant, on which you can clearly see the larvae. Then spray the plant well, including the underside of the leaves. Collect and dispose of all fallen borer caterpillars.

Further countermeasures

bacteria

To combat boxwood caterpillars, a bacterium is used as a biological spray that kills the moth caterpillars. It’s called Bacillus thuringiensis and is commercially available under various brands. The advantage is that it does not harm any beneficial insects.

application

  1. The most effective time to spray is when the larvae have hatched but are not yet too large. Infestation control is therefore important.
  2. It should not rain on the day of application and also in the following days, so that the agent remains on the leaves and is not diluted.
  3. The information on the correct dosage is taken from the packaging.
  4. When spraying, make sure that the boxwood is really dripping wet, even on the inside.
  5. Repeat the spraying after about 2 weeks to also combat the larvae that hatched later.
  6. The aim of the control measure is to interrupt the life cycle of the moths.
Tip: It can be helpful to remove the largest webs beforehand, otherwise they protect the borer caterpillars.

Algae lime

Whether algae lime helps is not entirely clear, but some gardeners swear by it. The remedy should be particularly effective after a strong pruning . The entire plant is dusted with the lime. It should be noted that too much lime can damage the box.

chemical sprays

Various chemical sprays are available on the market to combat the box tree moth. Among them are:

  • Acetamiprid
  • Deltamethrin
  • Pyrethrine
  • Thiacloprid

They usually work not only against the borer and its stages of development, but also against other pests. The application is similar to that of biological sprays.

Encourage natural enemies

When the box tree moth was introduced, it had hardly any natural enemies. Since it also absorbs poison when eating the poisonous book, it was long considered inedible for songbirds. In the meantime, however, more and more birds seem to be interested in the larvae, as some species have even been observed feeding the caterpillars to their young. For this reason, it makes sense to encourage the following bird species in the garden:

  • sparrows
  • tits
  • throttles
  • Stare
Tip: Birds need hiding places, nesting sites, a water point and possibly a feeding place in the garden.

Prevent

It is difficult to prevent an infestation by the box tree moth – and thus also caterpillars on the box tree. Close-meshed plant protection nets are best . However, these must be placed over the plants in good time in spring. Even then, success is not guaranteed because there may still be pupae in the plant from the previous year.

Pheromone traps , with which the male butterflies are caught, are also suitable for prevention and infestation control. They can then not reproduce with the female butterflies. However, they are not of much use if the moths are already laying their eggs.

frequently asked Questions

There is an obligation to report diseases or pests that are particularly dangerous or occur in large numbers. Since the box tree moth is not dangerous to humans or animals and does not cause any damage apart from the box, there is no obligation to report.
Box trees not only suffer from the moth moth, fungal diseases and climate change also affect it. So it makes sense to think about alternatives. These can be: Japanese holly, small-leaved rhododendron or the yew.

In most cases yes, but the shape of the boxwood can be affected. However, if the box is eaten bare again and again, the plant loses vitality and eventually dies.

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