Phylloxera caryae-foliae

Phylloxeridae

Phylloxera

Carya glabra

Alabama

Arkansas

Connecticut

Delaware

Florida

Georgia

Illinois

Indiana

Iowa

Kansas

Kentucky

Louisiana

Maine

Maryland

Massachusetts

Michigan

Mississippi

Missouri

New Hampshire

New Jersey

New York

North Carolina

Ohio

Oklahoma

Pennsylvania

Rhode Island

South Carolina

Tennessee

Texas

Vermont

Virginia

West Virginia

Wisconsin

Ontario

Carya laciniosa

Carya texana

Carya tomentosa

North American Phylloxerinae affecting hicoria (Carya) and other trees

Phylloxera caryaefoliae

Phylloxera caryaefoliae

Notwithstanding the apparently wide distribution of this species from New York to Illinois and as far south as Washington, it appears to be nowhere so common or so destructive as some of its near relatives. It is most noticeable during the latter part of May on the leaves of Hicoria glabra, and though usually there is but a single gall upon a leaf, as many as four may sometimes be found. Some which were studied on the 23d of May along the Potomac River in Virginia contained already quite a number of winged migrants, though the gall had not yet sufficiently opened at the apex to allow the inmates to escape. 

The principal part of the gall is always on the upper side of the leaf and represents a regular, slender cone which often leans slightly over to one side. The transverse diameter of the gall at the base of the cone is about 3 mm and, including the pale ring surrounding it, about 5 mm; and its vertical diameter is also about 5 mm. Its surface is more or less pubescent, more densely so beyond the middle. Its color above is pale green, with numerous still paler, extremely fine, radiating lines running from tip to base. The apex is either somewhat somewhat yellowish, pale brownish or pale purplish and the extreme base darker green. The ring surrounding its base is either somewhat projecting and slightly convex or sometimes depressed or saucer-like and of a yellow or greenish-yellow color. The under side of the gall is but slightly projecting and quite flat, with a small elevated ring surrounding a minute central depression from which rises a small nipple, splitting into a number of very fine and slender pubescent filaments. The walls of this gall are very thin and flexible and rather difficult to tear, especially when they commence to shrivel after having been taken off the tree for some time. They are stoutest at base and more or less transparent if held towards the light. That this species is closely related to Ph. c.-septum is quite apparent. The younger ones have also, as in that species, a transverse membrane which gradually disappears, leaving a distinct rim to indicate its position.

Phylloxera caryaefoliae

Carya sp.
Conical or globose leaf galls with distinct orifice and containing aphids
Galls conical above, opening on the upper surface, flat beneath, splitting into several bracts when mature, with slender filaments at the center beneath, walls papery, more or less transparent, diameter 5 mm.

Key to American Insect Galls

Phylloxera caryaefoliae Fitch   

Galls on leaves of Carya glabra project above leaf as pale green slender cones with pale rings at their bases, c. 5 mm diam., almost flat on underside of leaf with a central nipple.  Alatae emerge from the upper side of the gall (Pergande 1904) in early June.  In north-eastern USA (New York, Illinois, Iowa, Virginia).  The life cycle is unknown. 

Aphids on the world's plants

Phylloxera caryaefoliae

Hosts: Carya glabra, texana

Conical and pale yellowish-green above with a pale ring surrounding base, apex splits at maturity into several bracts, and diameter about 5.0 mm; flat beneath with a round opening surrounded by slender pubescent filaments.

Range: OK, SC, TX

Species Diversity of Hickory-feeding Phylloxerans (Hemiptera: Phylloxeridae) in the U.S.