This gallery contains 8 photos.
There are over 150 species cynipid wasps that induce galls on California oaks. Barely the size of fruit flies, these wasps cause some of the most exotic plant galls displaying a variety of shapes (conical, spherical, stalked, disc-shaped, spiny, etc.) … Continue reading
This gallery contains 4 photos.
A midge belonging to the genus Blaesodiplosis induces galls on the leaves of a shrub commonly called serviceberry (Amelanchier alnifolia). The hairy, white galls have red tips and are monothalamous (have only one chamber). The galls occur on the upper … Continue reading
This gallery contains 6 photos.
Alders along the shore of Manzanita Lake (Lassen Volcanic National Park) are heavily infested with alder cone gall fungus. Taphrina occidentalis is a sac fungus that induces flat, twisting galls on the bracts of alder cones. The cone bracts of … Continue reading
This gallery contains 6 photos.
The cedar quince/hawthorn rust (Gymnosporangium clavipes) is heteroecious, that is, it requires two different host species to complete its life cycle. The cedar quince/hawthorn rust winters as a stem gall on a juniper or a cedar host – its primary … Continue reading
This gallery contains 3 photos.
Juniper burr galls occur on the leaves (scales) of several species of junipers and are induced by a midge (Oligotrophus juniperi). Little is known about the life cycle (biology) of this midge. Generally, midge eggs are laid in or on … Continue reading
This gallery contains 3 photos.
Oak club galls form on several oak species when oak club wasps (Andricus coortus) lay their eggs at the tip of new stems in the spring. The oak club is a cynipid wasp. Adult club gall wasps emerge the following … Continue reading
This gallery contains 7 photos.
A gall formed on Oregon white oaks (Quercus garryana – see “Oaks in Spring” 03-05-14) by the cynipid wasp Trichoteras tubifaciens is the crystalline tube gall. A tubular-shaped gall covered in short, crystalline hairs, the crystalline tube gall ranges in color … Continue reading
