Diastrophus turgidus
Red raspberry knot gall wasp
Host: Red raspberry (Rubus strigosus).
Gall location: On the stem.
Description: Large, multiple-chambered swellings rather similar in appearance to the blackberry knot gall. Generally smooth and fleshy, but usually densely covered with thorns. Unlike the blackberry knot gall, the red raspberry knot gall lacks distinct longitudinal grooves and is instead rather regular in its surface texture. Reddish to greenish and fleshy when fresh to brown and dry when old.
Range: Likely widespread, thus far known along the border of the US and Canada as well as Alaska and some records from Central Canada.
This gall is rather poorly known, as demonstrated by its disparate range. The range and appearance of this gall separate it from the blackberry knot gall.
”- Louis Nastasi, Charles Davis: (2022) Field Guide to the Herb and Bramble Gall Wasps of North America©