Like the box tree moth and the box tree dieback caused by a fungus, the box tree spider mite is a relatively new species. Eurytetranychus buxi first appeared in Germany in 2003. The species probably got here through imports from North America and has been spreading ever since.
Spider mites are a fairly new pest for boxwood
appearance and lifestyle
Like all spider mites, boxwood spider mites are tiny and therefore easy to overlook. Females are between 0.4 and 0.5 millimeters in size, males remain smaller with an average of 0.35 millimeters. The animals are usually reddish-brown in color and react quickly to disturbances. The first generation hatches from the end of May, followed by another every four weeks. Between six and eight generations develop per season, with the most recently laid eggs hibernating on the plant and only hatching the following year.
damage picture
Spider mite damage typically manifests itself as tiny white or yellowish speckles on the upper surfaces of the leaves. They are often completely covered, then after a while they turn reddish to bronze and fall off. Other leaves, on the other hand, can only be slightly attacked. Eurytetranychus buxi rarely forms the characteristic fine webs. If such appear, it can also be an infestation with the box tree moth.
combat
The spider mite is comparatively easy to combat. Good results have been achieved with pesticides based on rapeseed or neem oil. These must be applied in early spring before April 15th or in autumn to kill the winter eggs and thus the first generation. If, on the other hand, the infestation is not noticed until later in the year, potash soap has proven its worth. This is contained in many remedies against aphids. A natural predator of the spider mite is the predatory mite Typhlodromus pyri, which is particularly hungry between mid-April and early May.
prevention
A spider mite infestation can be prevented quite well with the following measures:
- Ensure an adequate supply of water.
- Mulch boxwood beds to keep moisture in the soil longer.
- Pay attention to a balanced fertilization that is not overly nitrogenous.
- Choose a suitable, airy location.
- Keep the recommended planting distance.
- Encourage the settlement of beneficial insects in the garden, for example by setting up an insect hotel.
You should also check your Buchs regularly, if possible with a magnifying glass, in order to identify any infestation as quickly as possible and to take appropriate countermeasures.
tips
If you discover the characteristic symptoms of spider mite damage on your box trees, you should examine them carefully: animals are not always actually still there. Sometimes a phase of rainy, rather cool weather is enough to kill the warmth-loving spider mites.