More than 100 species of butterflies lay their eggs on the birch, from which caterpillars then hatch. The tree is therefore one of the most popular food plants for caterpillars. While butterfly caterpillars on birch trees are part of nature's constant cycle, wasp caterpillars can be dangerous to the tree.
There are caterpillars on my birch tree, what should I do?
It is usually not necessary to control the caterpillars as they cause little damage to the birch tree. Greater damage is possible from caterpillars of theGreat birch sawfly. Remove leaves with many caterpillars. If there is a severe infestation, use an environmentally friendlyPlant protection product
How do I recognize birch sawflies and their caterpillars?
You can recognize the large birch sawfly (Cimbex femoratus), also called birch button sawfly, and their caterpillars, often called anal caterpillars, by these features:
- Butterfly is comparatively large at 20 to 28 mm
- Thorax is shiny black, abdomen is reddish brown
- Antennae are black at the base, the rest is yellow
- last leg segments are yellow-orange
- Wings are sharp and have dark edges
- Caterpillars can beup to 45 mm long
- their basic color isgreen
- Back has narrow, dark, yellow-lined vertical stripes
- Body is covered with whitish warts
- Caterpillars are nocturnal and sit on the undersides of leaves during the day
The typical damage to the birch shows from the edgeeaten leaves.
How can I fight birch sawflies?
The caterpillars of the birch sawfly rarely cause major damage that justifies combating the moth and its offspring. But it can happen that they severely infest a birch tree and eat its crown bare in no time. Collect and dispose of caterpillars and leaves early on if you discover many caterpillars or eggs on the underside. If the infestation is advanced, you can use an approvedplant protection productbased on neem oil, which largely spares beneficial insects. A mixture ofwater and cooking oil can also reduce the feeding of the larvae.
What other caterpillars can I find on the birch tree?
Peeped Moth (Biston betularia)
- Body is long and thin,
- colored light green to dark brown
Birch Owl Moth (Tetheella fluctuosa)
- gray-green to beige-grey colored
- lighter underside
- white dots everywhere
- larger black dots on the back
- Caterpillars live between leaves spun together
Birch tooth moth/Birch porcelain moth (Pheosia gnoma)
- Body length is between 50 and 60 mm
- Coloring is violet, reddish brown or green; shiny
- wide yellow vertical stripe
- young specimens are paler and darken over time
Birch Sicklewing (Falcaria lacertinaria)
- young caterpillars are dark brown to black
- with light stripes on the back
- The body of older caterpillars is very unevenly shaped
- beige or darker colored
Tip
Prevent severe birch sawfly infestations in good time
After the leaves have sprouted, check the undersides of the leaves regularly in order to discover any egg clutches early on. A thinning cut in spring can also reduce the infestation.