- How do I recognize an infestation with the rose leaf scroll wasp?
- How can I effectively combat the pest?
Roses can be affected by a whole range of different diseases caused by fungi, viruses or bacteria. However, many types of damage can be attributed to certain pests - mostly insects - of which the rose petal wasp is one of the most common. An infestation with this insect is indicated by the typical curled leaves.
The larvae of the rose scroll wasp grow inside rolled up rose petals
How do I recognize an infestation with the rose leaf scroll wasp?
In the case of an infestation with the scroll wasp, the damage, the rose petals that are strongly rolled up in a tubular shape, appears mostly in the months of May and June. The leaves also yellow and eventually fall off over the summer. The typical curling of the leaves is caused by the laying of eggs by the sawfly: the insect lays about two to three eggs on the edge of each leaf and finally stings the main leaf vein in the middle. It is this stitch that causes the curl. In this way, the scroll wasp ensures that its offspring - greenish larvae up to nine millimeters long - are optimally protected. Finally, in autumn, the larvae go underground to pupate over the winter months. In the next year, new insects have developed from it, which infest the rose again.
How can I effectively combat the pest?
Effective control of leaf scroll wasps therefore means that not only the rose itself, but also the soil surrounding it is thoroughly worked - this kills any larvae that may be present and ensures that the infestation can no longer occur next year. In addition, you should always check the rose petals thoroughly for the first signs from the beginning of May and collect affected leaves immediately. However, if the infestation is very severe, in many cases only a pesticide can help. In late winter - ergo around February, if the ground is no longer frozen by this time, you should work the soil around the rose with a hoe or something similar to disturb the pupation of the animals.
tips
Never throw cut or collected diseased plant material on the compost - this not only makes it a good fertilizer, but a real breeding ground for numerous new infections. The larvae of the rose scroll wasp also overwinter in the comfortable environment of a compost heap.