Diastrophus bassettii
Dewberry crown gall wasp

Host: Common dewberry (Rubus flagellaris) and swamp dewberry (R. hispidus).

Gall location: On the crown, at the interface of the stem and root, either above or below the soil line. In rare occasions, this gall can be found further up on the stem and may be mistaken for the similar galls, especially if the host plant is not identified to species.

Description: Multiple-chambered, globular swelling. Sometimes nearly spherical, but usually appearing as an amorphous botryoidal cluster of kernel-like chambers. Greenish to reddish when fresh. Highly variable in size, usually 1-3 centimeters in diameter but occasionally larger.

Range: Historically, this gall has been found throughout the Northeastern United States, but some records suggest it occurs as far south as North Carolina.

This gall was rather poorly known until the recent past. They are often locally abundant, and can often be found by locating a single gall and following the stems to find additional galls, even on the same plant.

- Louis Nastasi, Charles Davis: (2022) Field Guide to the Herb and Bramble Gall Wasps of North America^©