Andricus cinerosus

Disholcaspis cinerosa

Cynips cinerosa

Arizona

California

Florida

Georgia

North Carolina

South Carolina

Virginia

Cynipidae

Disholcaspis

Quercus fusiformis

Oklahoma

Texas

Quercus virginiana

Alabama

Louisiana

Mississippi

New Mexico

Cynipid galls of the eastern United States

The Mealy Oak Gall on Ornamental Live Oak in Texas

Disholcaspis cinerosa (agamic)

C. cinerosa, n. sp.
"Globular, monothalamous galls, from three-fourths to one inch in diameter, the surface in recent specimens covered with a mealy grayish powder, which disappears when the galls have been long exposed to the weather; internally of a dense cellular structure, much like the galls of C. q. globulus; the rather large, centrally placed larval cell nearly or quite free." 

New Cynipidae (1881)

Holcaspis cinerosa (Bassett)

Cynips cinerosa
Andricus cinerosus

Gall. (Plate VII, Fig. 10.) Singly or in clusters of two or three on the twigs of live oak (Quercus virginiana). Monothalamous. Globular with a distinct pointed nipple at the apex, and covered with a dense mealy grayish powder. Internally it is of a dense corky or cellular structure, containing a partly free central larval cell. Diameter 12 to 22 mm. 

Habitat. Texas.

A distinct species, readily known by the dense grayish pubescence on the thorax and sides of the abdomen; clear hyaline wings with the cubitus of the primaries disappearing before reaching the first cross-vein. The gall is perfectly globular with a nipple at the apex and differs from all other known Holcaspis galls by the dense grayish powder covering it. 

The types are in the American Entomological Society. A fine lot of galls of H. cinerosa, from Austin, Texas, were kindly sent to me by Mr. C. Hartman.

The species of Holcaspis and their galls

Disholcaspis cinerosa

The large pointed-bullet galls of this species, described from an unknown oak, occur on Q. virginiana and have been seen at various points in Texas: Houston, Wharton, Victoria, Cuero, Boerne, Austin, Sabinal, Kerrville, Beeville, Tiger Mills, Columbia (E. A. Schwarz), and Quincy. A tree at Wharton contained hundreds of them in October, 1917. While growing they secrete honeydew and wasps frequent them in large numbers. J. D. Mitchell reared the adults at Victoria December 5-25.

Field notes on gall-inhabiting cynipid wasps with descriptions of new species

Disholcaspis cinerosa

Quercus virginiana, geminata
Stem galls, detachable
Diameter 19-24 mm, covered with a mealy gray powder which gradually weathers away. 

[Photo caption]
On Q virginiana in TX. Gall secretes honeydew. Some trees are loaded with hundreds of these galls. They contain 40% of tannic acid.  An adult emerged indoors Dec 30.

Disholcaspis cinerosa
Asexual generation

The asexual generation develops within mealy-oak galls on branches and branch lets of host trees (figure 1). These spherically shaped galls are familiar to people who live in cities where live oaks commonly are planted as ornamentals. Galls range from 1/8 to 1 inch in diameter and are first noticed in late summer or early fall, depending on locality. When first formed, they are small, light pink to pinkish brown and the internal tissue is soft (figures 1 and 3).

From late summer to late fall (figure 4) developing Disholcaspis larvae eat plant tissues within galls. From August to mid-October, internal gall tissue is yellow-green and moist (figure 3), while during late October and November the tissue turns brown and begins to dry (figure 4). During November, pupation occurs and shortly thereafter transformation to the adult stage takes place. During December and the first part of January, adults emerge by chewing holes at gall bases (figure 1). 

During the first winter, recently abandoned spherical galls begin to weather and in the process change from pink to grey and become dry and hard (figure 1). If left undisturbed, they may persist on host trees for several years. In essence, grey galls are inactive structures that serve to remind one of a past event. They actually assume a nonliving status about 1 month (November) before adults begin emerging from the galls.

Range: Gall-infested live oak trees occur throughout Texas in natural and planted situations. The gall wasp also is reported from the same host in certain parts of Mexico and from western Louisiana. 

Association with Quercus geminata possible based on the ambiguous implication in Weld 1959 that the entire list for Quercus virginiana also occurs on Quercus geminata, but not confirmed by later sources.

Association with Quercus fusiformis inferred from iNaturalist observations.

Gallformers ID Notes