(Pennisetia marginata)
The Pennisetia Marginata’s common name (Raspberry Crown Borer Moth or Blackberry Clearwing Borer) explains the host plant it attacks. It is a moth of the family Sesiidae, not a hornet like it appears to be. The species was first described by Thaddeus William Harris in 1839. It is widespread in the United States, but mainly in the east and along the American Pacific Coast; it is not common in the Western Pacific Coast of BC.
I captured this photo while I was photographing bees and hornets on the flowers around my yard last year. I was not aware that I had indeed gotten a photo of a moth instead. It was not until a year after that, I noticed differences in the overall look of this insect. I was pleasantly surprised to see just what was in the photo. I wish the wings had come out clearly.
Adults fly during August and September. They are active during the first day to mate, and then each female will lay about 150 eggs on the underside of raspberry leaves just at the leaf margins. The eggs are brown. After hatching, the larvae migrate to the base of the cane and find a protected place in the bark to overwinter. They bore into the crown and roots the following spring, and then over the next 2 years, they will continue to bore through the crown and roots, always working their way towards the fruiting canes. When larvae are mature and have reached a length of 30 mm, they will form pupae and emerge as moths in late summer. The life cycle may take two years to complete, but all life stages are present in any given year. They not only attack raspberries and blackberries but will bore into most other native fruit canes.