On willow I often find Twenty-spotted willow beetles. I also found these larvae on a White Willow. Are they from the Willowbeetle?
Answer
Dear Sonja,
If you have observed adults of Chrysomela vigintipunctata, the larvae can indeed come from this species, but this is very difficult to confirm based on photo material. Even by stereomicroscopic examination this is not self-evident.
After all, many leaf beetles (Chrysomelidae) occur on willows, including Chrysomela, Phyllodecta, Plagiodera and Galerucella species. The identification of the adult stages is often very difficult because of the sometimes great similarities.
Identification of the larvae is usually even more difficult, on the one hand because most of the larvae resemble each other, and on the other hand because of the lack of good identification keys.
Kind regards,
Hans
Answered by
Hans Casteels
identification of pest insects in agriculture and horticulture, stock goods and homes
Burg. van Gansberghelaan 96 box 1 9820 Merelbeke
http://www.ilvo.vlaanderen.be
.