Walshomyia cupressi
This gall midge induces large, monothalamous, four-sided galls in summer on at least two cypress species.
They appear as massive replicas of the terminal buds and often occur in clusters of three or four individual galls.
Galls at different stages of development can be found from spring through fall.
Vigorously growing cypress trees seem to host more galls than stunted specimens nearby.
Hosts:
Hesperocyparis pygmaea (Mendocino cypress)
Hesperocyparis sargentii (Sargent cypress)
- Russo, Ronald A. : (2021) Plant Galls of the Western United States©