plant bug

Plagiognathus blatchleyi is a small plant bug. It occurs in the United States from New York south to Virginia and Tennessee, and west to Colorado and Texas, and in southern Canada from Quebec to Manitoba.

Host preferences for Plagiognathus species are not well documented. Many feed on a single woody plant species, but some feed on a variety of annual plants. Plagiognathus blatchleyi has been recorded feeding on giant ragweed and wingstem, both in the family Asteraceae.

Adults are ⅛″ to 3⁄16″ (3.76 to 4.44 mm) in length. That is small for a plant bug (family Miridae) but relatively large for one in the genus Plagiognathus. The body is soft, broad, and deep, appearing “heavy”, and it is more or less parallel sided. The coloration is yellowish or faintly greenish (pale) and brown (dark).

The head is short, wider than long. The mouth parts are optimized for piercing and sucking. They take the form of a long, 4-segmented beak. When not used, the beak extends from the front of the head, along the underside of the body between the legs, to the tip of the first segment (coxa) of the hind legs. The antennae are slender and relatively long. The first two antennal segments are dark except for a pale ring at the end of the first segment. The plate on the face (clypeus) is chestnut brown, contrasting with the remainder of the head, which is light green or dark olive green.

The pronotum is distinctly divided. The front one-quarter to one-third (front lobe) is the same color as the head. The rear lobe is variable, from mostly pale but dark at the rear corners, to almost entirely dark.

There are two pairs of wings, and they are held flat over the body when at rest. Between and at the wing bases there is a triangular plate (scutellum). The scutellum is entirely pale. The front wings (hemelytra) have a thickened section at the base and a thin membranous section at the tip with a clear dividing line between the two. The thickened basal part is comprised of a narrow area (clavus) behind the scutellum when the wings are closed, and the remaining broad marginal area (corium). At the end of the corium there is a small but distinct triangular area (cuneus). The elytra are mostly pale. The rear two-thirds of the clavus and the rear one-third of the corium are dark. The cuneus is entirely pale. The membrane is dark with pale veins that weakly to moderately contrast with the dark membrane. The hind wing is completely thin and membranous.

The legs are pale with dark spots. The third segment (femur) is sometimes darkened. The fourth segment (tibia) is dark just at the base. It has two rows of spines, and there is a dark spot at the base of each spine.

Total length: ⅛″ to 3⁄16″ (3.76 to 4.44 mm)

Giant ragweed and wingstem

Sources

24, 27, 29, 30, 82, 83.

Revision of New World Plagiognathus ... and the description of a new genus (Heteroptera, Miridae, Phylinae) Schuh, R.T. 2001. Bulletin of the AMNH, 266: 1-267.

This species has no common name. The common name for the family Miridae is plant bugs, and it is applied here for convenience.

Alfredo Colon
8/6/2019

Location: Woodbury, MN