Rose petals curl up | Leaf scroll wasps on roses

When the rose petals roll, extreme caution is required. Although an infestation of Blennocampa pusilla does not damage the entire plant, it does damage the optics. So that the roses are not attacked by leaf scroll wasps every year, it is also important not only to initiate control when the damage is detected, but also to take preventive measures for the following years. Therefore, the following steps are particularly important:

• detect damage
• Identify leaf scroll wasps
• Fight
• Prevent
• create a natural garden

detect damage

Not only the adults are to blame for the damage to the leaves, but also their larvae. In May, the females lay their eggs on the leaf stems and also poke holes in the rose petals. These roll up and protect the larvae. The hatched larvae are greenish mottled and snail-like and are between six and ten millimeters long. The individual rose petals are usually attacked by one to three larvae. These eat away at the top layer of the rose petals, resulting in the following damage:

• Rose petals curl up in a tube
• on both sides of the midribs
• later only thin membranes remain
• so-called skeleton or window damage
• turn yellow
• fall off

Identify leaf scroll wasps

Blennocampa pusilla are inconspicuous, small insects about four millimeters in size that hatch in April from the soil where they have hibernated under the rose bushes. The adults are black and fly around between April and May to lay their eggs on the roses. They are usually not seen on the rose bushes because they only lay their eggs here and then leave the roses and die. The adult roller wasps therefore do not feed on the rose petals or other parts of the rose. The only damage is caused by the larvae.

Fight

Fighting rose leaf scroll wasps with chemical or household remedies is not that easy. Because there is no really good means of combating it here. However, there are mechanical control methods that are very effective, but unfortunately also very labor intensive. These should be initiated immediately upon detection of the damage and look like this:

• remove any rolled leaves from the bush
• cut off by hand
• alternatively cut whole shoots
• by July at the latest
• then the larvae pupate
• fall off
• Do not put leaves in the compost
• the wasps could continue to hatch here
• Dispose of well-packaged leaves in the household waste
• or burn in the grill

Prevent

Prevention is also important. Above all, this includes strengthening the roses with the right fertilizer and the right soil conditions. Only healthy plants can defend themselves against an infestation. Undersupplied roses, on the other hand, are an easy target for pests and diseases of all kinds. It is important to prevent lime deficiency and avoid nitrogen-rich fertilization. Mulching and nettle manure are excellent preventive measures for healthy roses. If countermeasures have already been taken to treat infested roses, you can continue to take preventive measures for the next year as follows:

• remove soil after July
• it is always possible that pupated larvae have fallen off
• Stop using the soil
• dispose of in household waste
• Squirt vermouth or tansy broth
• Horsetail tea also effective
• directly on the remaining leaves
• in the spring directly on the new growth

Create a natural garden

Even if it sounds suspicious to ban the leaf scroll wasps from a natural garden and to prevent them with this, this is still a good method. Many natural enemies of Blennocampa pusilla can be found in near-natural gardens, as this is in a natural balance. Natural stone walls, small pieces of wood, bird nest boxes and other shelters help the following natural predators of the small pests to settle:

• blue tits
• birds in general
• Beetle
• Spitzmäuse
• be crazy
• Hedgehog
• caterpillar flies
• parasitic wasps