Rose Bedeguar Gall / Ružina osa šišaruša

Description:

It develops as a chemically induced distortion of an unopened leaf axillary or terminal buds, mostly on field rose (Rosa arvensis) or as here on the photo dog rose (Rosa canina) shrubs, caused by the parthenogenetic hymenopteran gall wasp (Diplolepis rosae L., synonyms are: Diplolepis bedeguaris, Rhodites rosae or Cynips rosae). Females lay up to 60 eggs within each leaf bud using their ovipositors. The asexual wasp emerges in spring; less than 1% are males.

Habitat:

The galls occur more commonly on plants under stress, i.e. very dry conditions, waterlogging or hedge cutting, whereas vigorously growing plants are less commonly found to have galls. Whether the vigorous plant suppresses gall formation or is avoided by the wasp in favour of easier targets is unknown. Young and damaged plants tend to produce larger and more numerous galls than old and intact ones. Many eggs are laid, but the number of galls formed is relatively few.

Notes:

Dried and powdered, the gall was used as to cure colic, as a diuretic, and as a remedy against toothache; the ashes mixed with honey and applied to the scalp were thought to prevent baldness. It was also valued as an astringent and for its ability to control fluid loss; placed beneath a pillow, it was thought to induce sleep.