How do I recognize an infestation with the rose petal wasp?
If the leaf wasp is infested, the damage pattern, the strongly tubularly rolled rose petals, usually appears in the months of May and June. The leaves also turn yellow over the course of summer and eventually fall off. The typical curling of the leaves is caused by the sawfly laying their eggs: the insect lays around two to three eggs on the edge of each leaf and finally sticks into the main leaf vein in the middle. It is this stitch that causes curling. In this way the sawfly achieves that its offspring - up to nine millimeters long, greenish larvae - are optimally protected. In autumn, the larvae finally disappear into the ground to pupate over the winter months. In the next year, new insects developed from it and attacked the rose again.
- Rose petal wasp - recognize, control, prevent
- Yellow leaves on the rose indicate a lack of nutrients
- Rose diseases: prevent them in good time in early spring
How can I fight the pest effectively?
Therefore, an effective control of the leaf wasp includes that not only the rose itself, but also the surrounding soil is thoroughly worked - in this way you kill any larvae and ensure that the infestation can no longer occur in the next year. You should also check the rose petals thoroughly for the first signs from the beginning of May and collect the infected leaves immediately. However, if the infestation is very pronounced, in many cases only a pesticide will help. In late winter - i.e. from around February, if the ground is no longer frozen at this point, you should work the earth around the rose with a hoe or something similar to disrupt the pupation of the animals.
Never throw cut or collected, diseased plant material on the compost - in this way it not only develops into a good fertilizer, but also into a breeding ground for numerous new infections. The larvae of the rose petal wasp also overwinter in the comfortable surroundings of a compost heap.