Spider mites usually attack hydrangea when the plants are overwintered indoors. The tiny mites prefer dry air and can damage the hydrangea so badly that it even dies. That's why quick action is required in the event of an infestation.
How can you combat spider mites on hydrangeas?
To combat spider mites on hydrangeas, you should shower the affected plant, lower the room temperature and water the hydrangea regularly. If the infestation continues, cut off affected parts of the plant and treat the hydrangea with a special pesticide.
The Pest
Spider mites are widespread pests with more than a thousand species worldwide, of which only two are important in our latitudes. These are:
- Common spider mite (Tetranychus urticae)
- Fruit tree spider mite (Panonychus ulmi)
The approximately 0.5 millimeter large, oval mites are yellow-green, brown or bright red, especially in winter.
The harmful image
Spider mites prefer to settle on the underside of the hydrangea leaves. As a result, they are often only noticeable when the leaves are covered by a fine white web during severe infestation. The mites pierce the plant tissue to drink the plant sap. This causes light green spots to become visible on the top of the leaf, which enlarge and merge over time. The hydrangea's foliage turns yellow and dries up. The animals protect themselves with fine white webs that look very similar to spider webs.
Prevention
If the hydrangea is attacked by spider mites in winter, it is usually too warm. The animals prefer dry air, so you should water the plants regularly, even in winter. Make sure the hydrangea is in good condition before moving to winter storage. He althy and strong plants have natural protection against harmful insects.
Check the undersides of the leaves cyclically with a magnifying glass. The animals are so tiny that they often cannot be seen with the naked eye. If the characteristic webs appear, the infestation is usually already well advanced.
Combat
To combat pests, follow these steps:
- Shower affected plants with a sharp spray.
- Since spider mites don't like moisture, repeat this procedure every few days.
- Reduce the room temperature or keep the hydrangeas cooler.
Isn't this enough:
- Cut off affected plant parts and dispose of them in household waste or burn them.
- Treat Hydrangea with a special pesticide (€28.00 on Amazon).
Since the mites are mainly located on the underside of the leaves, it is important not only to wet the surface of the plant but also to spray all the leaves thoroughly from below.
Tips & Tricks
A good prevention is plant protection sticks that are stuck into the ground. They release an active ingredient over months that is absorbed by the hydrangea. This provides excellent protection for the hydrangea against pest infestation.
