Roses can be affected by a whole range of different diseases caused by fungi, viruses or bacteria. However, many of the damage can be attributed to certain pests - mostly insects - of which the rose leaf wasp is one of the most common. An infestation with this insect can be seen in the typical curled leaves.
What causes curled leaves in rose diseases?
Rolled leaves on roses can indicate an infestation of the rose leaf wasp. Typical signs are tubular, curled leaves that yellow and fall off over the summer. Infected leaves should be removed and the soil around the rose worked to kill larvae.
How do I recognize an infestation with the rose leaf wasp?
When infested with the leaf roller wasp, the damage occurs: rose petals rolled up in a very tubular shape, usually in the months of May and June. As the summer progresses, the leaves also yellow and eventually fall off. The typical curling of the leaves is caused by the sawfly laying its eggs: the insect lays around two to three eggs on the edge of each leaf and finally stings the main leaf vein in the middle. This stitch is what causes the curling. In this way, the sawfly ensures that its offspring – greenish larvae up to nine millimeters long – are optimally protected. In autumn, the larvae move into the ground to pupate over the winter months. The next year, new insects have developed from them and attack the rose again.
How can I combat the pest effectively?
That's why effective control of the leaf rollerfly requires not only the rose itself, but also the soil surrounding it to be worked thoroughly - this way you kill any larvae that may be present and ensure that the infestation does not occur next year more can occur. In addition, from the beginning of May you should always check the rose petals carefully for the first signs and immediately collect any affected leaves. However, if the infestation is very severe, in many cases only a pesticide will help. In late winter - around February, as long as the ground is no longer frozen at this point, you should loosen the soil around the rose with a hoe (€139.00 at Amazon) or similar.edit to disturb the pupation of the animals.
Tip
Never throw cut or collected diseased plant material onto the compost - in this way it not only becomes a good fertilizer, but also a breeding ground for numerous new infections. The larvae of the rose leaf wasp also overwinter in the comfortable environment of a compost heap.
