Parasitism of Euschistus heros (F.) adults was studied in Londrina, PR. Twenty males and 20 females were collected each week from November 1996 to December 1997. In the laboratory, adults were sexed and maintained in plastic box (12 x 12 cm) with humidity and soybean pods as food, and observed daily during 30 days. The encyrtid Hexacladia smithii Ash. was observed attacking the bugs, being the first register of parasitism by Hexacladia in this host. The natural incidence of parasitism varied from 0.6% to 39.5%. Higher abundance of the parasitoid occurred during December and January and it was drastically reduced (<1%) from May to September. Males and females were equally attacked by the parasitoid (14.7% and 11.9%, respectively). H. smithii is a gregarious endoparasitoid that completed its development inside the host body. Adults emerged through a hole in the ventral or dorsal surface of the abdomen. From 2 up to 39 parasitoids were observed to emerge from a single adult E. heros.
Insecta; biological control; natural incidence; stink bug; soybean
