Horizontal transmission of the entomopathogenic fungus Beauveria bassiana (Unioeste 76 strain) among adults of Euschistus heros (Fabricius, 1798) (Hemiptera: Pentatomidae).

Abstract

The horizontal transmission of the entomopathogenic fungus Beauveria bassiana Unioeste 76 strain among adults of Euschistus heros was evaluated in the laboratory and greenhouse using sporulated cadavers and live insects contaminated as a source of inoculate. Adult insects in the laboratory bioassay either received treatments with dry conidia or were sprayed with an oily dispersion formulation, and the treatments were comprised of 10, 30, or 50% of contaminated insects. For the greenhouse bioassay, nylon cages were prepared, with soybean plants grown in pots. A total of 20 healthy brown stink bugs were released along with one or three sporulated cadavers of brown stink bugs, attached to the plant stem. In the bioassay with live insects, 20 stink bugs were released, and the treatments were comprised of 10, 30, or 50% contaminated insects (2:18, 6:14, and 10:10, fungus-treated insects : healthy insects). In all experiments, the control group was comprised only of healthy insects.