During soybean field scouting, a small black insect can be observed in relative abundance in 2021. This insect is known as the white-margined burrower bug, Sehirus cinctus (Hemiptera: Cydnidae) (Figure 1). This insect is not a pest of soybeans but is observed in many other crops, including wheat and hemp (personal observation).
White-margined burrower bug is a univoltine species that overwinters in soil in areas where purple deadnettle (Lamium purpureum) (Figure 2) grows. Adults and nymphs feed on the seed of this plant. After the overwintering period, they become active in early April and reproduce shortly thereafter. White-margined burrower bug females exhibit well-defined maternal behavior. Eggs are laid in a loose cluster in small burrows in the soil. Females respond defensively to intruders by shielding the eggs with their bodies, guarding them from the time of incubation up until they are in the second instar. The female forages and provides the burrow with purple deadnettle seeds. Several days later, nymphs disperse, and maternal behavior ends.
By Raul T. Villanueva, Entomology Extension Specialist