These photos show a small parasitic worm, or larvae, the tiny white object in the middle of the orange woody, furry, ball (in photo on right) which are growing on the wild roses, among the rose- hips.
This is the rose bedeguar gall, Robin’s pincushion gall, or moss gall. It develops as a chemically induced distortion of an unopened leaf axillary or terminal bud, mostly on field roses (Rosa arvensis) or on dog rose shrubs (Rosa canina). It’s caused by the parthenogenetic hymenopteran gall wasp (Diplolepis rosae – Linnaeus, 1758). The insect is also called bedeguaris, Rhodites rosae or Cynips rosae.
In May, the Diplolepis insect females lay up to 60 eggs in each leaf bud and the larvae over-winter in these furry-looking balls, emerging again the following spring. The wasp is asexual, less than 1% are males, and it will also attack garden rose cultivars. So, we’ll cut off all the gall balls we can see and put them on the fire!