Michigan State University Extension
Ornamental Plants plus Version 3.0 - 00001727
11/12/99
Gall wasps
Adults are small (1 to 3 mm), black wasps that usually go
undetected by the average homeowner. Gall wasps insert
their eggs into plant tissue. When larvae emerge from the
eggs, they produce chemicals that induce the host plant to
grow abnormally, producing galls. The larvae develop
inside the galls. Galls induced by these wasps may appear
as spherical stem galls, starlike leaf galls or horny twig
galls. Oak trees in particular seem to host a large
number of gall wasp species. If you cut a gall open at
the proper time, you'll find a tiny (1 to 2 mm), white,
legless, worm-like larva. If you place suspect galls in a
glass jar, you may capture the adult wasps when they
emerge.
This information is for educational purposes only. References
to commercial products or trade names does not imply
endorsement by MSU Extension or bias against those not
mentioned. This information becomes public property upon
publication and may be printed verbatim with credit to MSU
Extension. Reprinting cannot be used to endorse or advertise
a commercial product or company.
This file was generated from data base ZZ on 01/19/00.
Data base ZZ was last revised on 11/12/99.
For more information about this data base or its contents please contact
heatley@msue.msu.edu . Please read our
disclaimer for important
information about using our site.