Neuroterus noxiosa

Noxious oak gall

Neuroterus noxiosus form vernalis

Neuroterus batatus form vernalis

Neuroterus batatus variety noxiosus

Cynips noxiosa

	Neuroterus noxiosus

Cynipidae

Neuroterus

Quercus bicolor

Alabama

Connecticut

Delaware

Illinois

Indiana

Iowa

Kentucky

Maine

Maryland

Massachusetts

Michigan

Minnesota

Mississippi

Missouri

New Hampshire

New Jersey

New York

North Carolina

Ohio

Pennsylvania

Rhode Island

South Carolina

Tennessee

Vermont

Virginia

West Virginia

Wisconsin

Nova Scotia

Ontario

Quebec

Quercus lyrata

Arkansas

Florida

Georgia

Louisiana

Oklahoma

Texas

Cynipid galls of the eastern United States

The North American Species of Neuroterus and their Galls

Life histories of American Cynipidae

Neuroterus quercusbatatus (sexgen) (q-bicolor)

Cynips noxiosa, n. sp.

[Cynips noxiosa (Neuroterus quercusbatatus) agamic galls] are invariably preceded by a vernal crop, which affects the leaves only, and which may be described as follows: Gall, an enormous development of the mid-vein of the leaf, often to the extent of an inch in diameter and an inch and a half in length. Green, smooth, but irregular in shape, and succulent and a little harder than a green grape. The blade of the leaf dwarfed and curled, and after the galls mature drying up. In some years these galls are so abundant on certain trees as to affect nearly all the vernal leaves, but a later crop hides the blighted appearance they produce. They are filled with larval cells, from which are produced vast numbers of male and female gall flies, about the 20th of June. Long observation has satisfied me that this is the bisexual generation of C noxiosa. 

New Cynipidae (1881)

Neuroterus noxiosus (Bassett)

Cynips noxiosa
Neuroterus noxiosus
Neuroterus noxiosa

Gall. Vernal form. (Plate IX, Fig 8 [Beutenmuller's Figure 7 is included here as well; it also clearly seems to depict this summer form despite the caption]). The gall is an enormous development of the mid-rib on the petiole of the leaves. It is green, succulent and irregular in shape. The blade of the leaf becomes dwarfed and curled, and after the galls mature the leaf becomes shriveled and dried.

Habitat. New England and Middle States westward to Iowa

This species is double brooded, the first brood appearing in May from the large woody galls of the previous year's growth, and the second brood in June from twigs formed on the leaves and tender twigs.

Neuroterus noxiosus form vernalis, new name

Galls. — Irregular clusters of woody swellings (Figs. 14 to 16) of the stems, petioles, and leaves. Polythalamous. The whole mass roughly about 20X40 mm. in diameter or less, inseparable from the plant; fist-like, the separate parts woody, indicating the separate leaves or parts of leaves involved, and bearing a small portion of deformed leaves; these parts are united by the deformed petiole, or by a fused mass of petioles or young twigs. The gall is bark-colored, or tinged with a glaucous bloom. Internally the larval cells are crowded closely together, the cells very distinct but not separable from the surrounding woody tissue. On the young growth of Quercus Prinus and Q. bicolor. 

Range: MA, RI, CT, NY, NJ, New Brunswick, IL, IO, MI

When Bassett first described this species he gave detailed descriptions of the galls of the two generations and noted differences in sizes of the adults. The specific relations of the two generations had been arrived at through the field observation of the alternate abundance of the two forms of galls and the close similarity of the adults of the successive generations. The tremendous abundance of this species locally often gives abundance opportunity for observations. Gillette, Beutenmuller, Miss Clarke, Thompson, and other students of the family have made observations confirming Bassett’s statements, and there can be no doubt of the regular alternation of these forms, even though the data has not been checked by experimental work. This was the fourth and last in- stance of heterogeny discovered by Bassett. 

The galls of this form appear when the young leaves first unfold in May and, like most of the spring galls of dimorphic species, grow very rapidly to maturity. The adults are known to emerge from June 12 to July 5. They occur in about equal numbers of the sexes: I counted 276 females and 233 males in one lot bred by Millett T. Thompson. After fertilization the females oviposit in the new wood of the twigs, usually not far from the galls in which they have developed. 

Neuroterus batatus variety noxiosus
bisexual form vernalis Kinsey 

Involved, without distinctive name, in most references to the agamic form. 
Neuroterus noxiosus form vernalis

Gall.--As described for the species; twisted, moderately woody, on young stems, petioles, and leaf-midveins of Quercus bicolor. This gall starts growth in May, the insects emerging from June 12 to July 5.

Range.--MA, RI, CT, NY, NJ, New Brunswick

The Gall Wasp Genus Neuroterus

Neuroterus noxiosus (Bassett)

By May 30 a slight bulging of the midrib of the young leaves then an inch and a half long has been noted and the galls of the alternating generation are full grown by June 30, greatly deforming the leaves. The adults emerged June 12- July 3. 

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

Sex. gen. of Neuroterus noxiosus (Bass.)

Midrib or petiole swellings.
NOXIOUS OAK GALL. Fleshy smooth green swellings of midrib on under side causing the leaves to curl. Developing with the leaves in early spring, full grown during June, adults emerging June 12-July 3. On Q. bicolor. 

Cynipid Galls of the Chicago Area

Neuroterus noxiosus Bass
Bi-sexual form, vernalis Kins

Gall, nearly as above [irregular, elongate woody swellings of young stems and sometimes petioles]

Adults, June to July 

On Q prinus [montana], bicolor

Plant Galls and Gall Makers

Neuroterus noxiosus (Bass.) 

Quercus bicolor, prinus
Leaf galls, integral
Sex. gen. Fleshy enlargement of midrib, green, smooth, bare. In May.

[Photo caption]
Fig 121. Agamic. On Q. bicolor. The woody galls persist over winter. Photo also shows the smooth fleshy galls of the alternating generation on the leaves. 

On Quercus bicolor, the gall formerly known as Neuroterus noxiosus causes green swellings on midribs and petioles of the leaves, causing them to curl and bunch substantially, though they typically still reach nearly their full size. In the winter, these deformed leaves persist on the tree, unlike leaves associated with N quercusbatatus on other white oaks.

The extent of morphological overlap, if any, between these fleshy sexual generation Neuroterus quercusbatatus galls on the petioles and midribs of Quercus bicolor leaves and Andricus quercuspetiolicola, is unknown. Many A q. petiolicola galls are clearly distinguishable by their large size, smooth surface, lack of leaf deformation, and conical shape ending in a pronounced indentation. However, some galls that otherwise seem to match Neuroterus quercusbatatus have fairly regular spherical shapes that could be confused with A q. petiolicola galls, especially after the wasps have emerged and the galls have begun to dry out. 

Quercus lyrata added tentatively as a host based on [this unconfirmed observation](https://www.inaturalist.org/observations/45557260). 

Gallformers ID Notes