Curled leaves on roses are not a pretty sight. But they are much more than just visual flaws - in many cases the sawfly is to blame.
Curled leaves on roses – signs of an infestation
Rose sawflies are tiny insects that grow to a maximum length of 4 mm. The pest lays its eggs on rose plants and attacks both shrubs and climbing roses and flowers. The many small, white dots on the underside of the leaves can hardly be seen with the naked eye. However, when the wasp larvae hatch, you can see them. They are about 1 cm long and have a yellowish-white body with geometric patterns. These small larvae eat the rose petals and can cause damage. After the larvae receive the necessary nutrients, they fall to the ground and overwinter in the soil.
The life cycle of the pest determines the time of infestation
The life cycle of the rose sawfly also determines when you can first see the damage to the roses. The insects appear in spring and lay their eggs on the underside of leaves around the end of April. The larvae hatch shortly afterwards - in May and help themselves to the fresh rose petals. The second generation hatches at the beginning of July - then you can speak of an infestation for the second time.
Are your roses losing leaves? This is what you have to do!
The larvae of the rose sawfly only eat the upper layer of the leaves, releasing chemicals that can damage the leaves. This first becomes noticeable with brown spots on the leaves, then individual areas of the leaf become transparent. Since the upper leaf layer is missing, the leaves curl up, slowly dry out and fall off.
The plants stop growing and instead put their energy into forming leaves. Although it happens very rarely that one is stronginfected rosedies, but is weakened. The growth has stopped, the flowering period is shorter and the rose looks sleepy and sick. That's why you should remove the pests if they are infested (without killing them). Fortunately, this task is very easy. You have to cut off the affected leaves and throw them away with household waste. This should happen once a week during the active phases - May and July. Otherwise the pests will hide in the ground. You will then have to expect an infestation again next year.
You can transplant the rose so that the pests also attack the neighboring plants. The minimum distance to other rose plants in pots or to outdoor plants is 2 meters.
Prevent curled leaves on roses: Tansy decoction protects against pests
Tansy is a poisonous plant that can protect roses from pests. You can make a brew yourself. For this purpose simply:
1. Place about 50 g of tansy - it is best to use dried leaves and flowers in a medium-sized pot.
2. Pour 500 ml of lukewarm water over the leaves and flowers and bring to the boil over medium heat. Then let it simmer for about 30 minutes. Remove the pot from the heat and let it cool.
3. Strain the liquid and then pour it into a clean screw-top jar. Store in a cold, dark place for about 2 months.
4. If there are signs of an infestation, pour 60 ml of decoction and 360 ml of water into a spray bottle and wet the rose petals and shoots well. Wait about a week and then repeat the process if necessary.
Fight the rose sawfly with natural enemies
Birds are natural enemies of the pest. You can keep the number of rose sawflies to a minimum and thus protect the plants. So make your garden as varied as possible. Birds don't need feeders in summer, but you can place bird baths near the roses. Tall bushes and hedges provide hiding places and nesting places for birds.
Another way to get rid of wasps is to loosen the soil regularly. This means that the birds can find the larvae in the ground much more quickly.
