Stem Borer

The adult stem borer is about 5/8 inches long long with long banded antennae. Photo by Phil Sloderbeck, © Kansas State University

The soybean stem borer is a native species that is widely distributed across North America east of the Rocky Mountains. It has been reported as an occasional pest from several southern states and has recently emerged as a major pest of soybeans in several Kansas counties.

Other names for the pest include the soybean stem girdler and Dectes stem borer. It belongs to the family Cerambycidae or long horned beetles, which is descriptive of the long antennae found on the adult beetles .

The small, bluish gray beetle lays its eggs in the petioles of soybean leaves. The larvae tunnel down to the base of the plants, eventually girdling the stem just above the soil line. Lodging occurs as the plants mature, making harvest difficult and reducing yield.

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