Is your pasture looking worrying lately? There may be a pest infestation. Although willows are actually quite resilient to disease, their leaves are occasionally plagued by numerous beetles that can cause serious damage. Here you can find out how to recognize the parasites in good time and get rid of them.
The willow gall sawfly can be recognized by the red pustules on the undersides of the leaves
Common Pests
- the blue willow leaf beetle
- the willow sawfly
- the willow gall sawfly
- the willow borer
The blue willow leaf beetle
You can recognize the pest Phyllodecta vitellinae with the naked eye by the three to six centimeter large, bronze, copper or blue colored larvae. Furthermore, the famous window corrosion is also visible. The beetle feeds on the leaves, which then turn brown. The first generation hatches in May or June, while the second is not long in coming in late autumn or winter. Older willows usually do not suffer much damage. In young trees, however, an infestation can lead to death. That is why even fungicides are approved for treatment. But think carefully beforehand whether you really want to use them.
The willow sawfly
The larvae of the Nematus pavidus are considered to be particularly voracious. From the edge of the leaf, they eat their way down to the veins, leaving little residue of the foliage. The six to seven millimeter large pests have a striking appearance:
- glossy black head
- black dots
- mainly green in color
- with orange or yellow body parts
- black vertical stripes on the back
This beetle also occurs in two generations. Once it affects the pasture from April to June, a second time from August to September. Large trees show comparatively little leaf loss. The treatment of young trees is similar to that of the willow leaf beetle.
The willow gall sawfly
Are there reddish growths or deformed leaves on your pasture? Then there is an infestation of the willow gall sawfly. The symptoms appear primarily in June. The black wasp lays its larvae on the leaves as early as May. Although their infestation leads to an unsightly appearance, you do not have to fear major damage. Therefore no treatment is necessary.
The willow borer
The brown moth with a wingspan of up to 10 cm lays its eggs under the bark of the willow. From then on, the 7 cm long caterpillars eat their way through the wood and leave behind finely crumbly substances. In the early stages you should try to remove the larvae manually. In the worst case, the only way to prevent further spread is to cut down the pasture.