The larvae of the rose sawfly (Caliora aethiops) feed on the top of the leaf and cause unsightly damage. These dry out after a while and leave holes. Infected leaves should be removed and disposed of with household waste, never in the compost. The larvae continue to develop there, promoting an infestation next year.
How can you get rid of rose sawflies naturally?
The natural control of the rose sawfly (Caliora aethiops) includes measures such as establishing beneficial insects and animals, setting up insect hotels, removing infected leaves, disposing of clippings with household waste, tilling the soil in late winter and using field horsetail tea or oak manure.
Biology and harmful effects
The greenish, approximately ten millimeters long larvae - the actual pests on rose petals - can be easily seen with the naked eye, completely different from the adult, black animals, which are only around five millimeters long. These fly from April, or earlier if the weather is right, and lay their eggs on the top and bottom of the roses. From May and June onwards, you can finally recognize an infestation by the cockroach damage, especially on the edges and tops of the leaves. Veritable holes appear in the leaf, with the rose slowing down or even stopping its growth in the event of a severe infestation. The larvae burrow into the ground around the rose in autumn and pupate there during the cold season, then return to haunt the rose the next spring as adults.
Fight rose sawfly naturally
The rose sawfly can be easily controlled naturally, with the following measures in particular having proven to be effective:
- Promote the settlement of beneficial insects (e.g. parasitic wasps), birds and hedgehogs in the garden.
- Set up insect hotels, piles of brushwood and leaves in garden corners.
- Feed the songbirds in winter, but stop feeding when the leaves emerge.
- Collect the larvae.
- Remove infected leaves and shoots.
- Dispose of the clippings only with household waste,
- this should help prevent a new infection.
- Collect fallen leaves and dispose of them with household waste.
- Till the soil in late winter to disrupt pupation.
- Spray the roses with horsetail tea for prevention and strengthening.
- If an infestation has already occurred, a treatment with oak manure helps.
Make oak manure
Collect about a kilogram of oak leaves and pieces of bark and let them ferment in water (preferably collected rainwater) for 14 days. The manure should be left covered and stirred daily. After 14 days, dilute the brew in a ratio of 1:10 with water and use it to treat your infected roses.
Use pesticides only in very severe infestations
Pesticides not only kill rose sawflies and other pests, but also kill beneficial insects. However, these are important to prevent further infestation. That's why you should avoid using substances that are harmful to the environment as much as possible; after all, with a little effort, this parasite can also be easily combated with home remedies.
Tip
If the rose petals curl up, there is probably an infestation with the rose leaf wasp.
