4.3.1. Impregnated-Paper Assay

The impregnated-paper assay was performed by following the method of Kljajic and Peric [55] and FAO [56]. Filter papers, Whatman No. 1 (9 cm in diameter), were submerged in various concentrations (5, 2.5, 1.25, 0.625, 0.312, 0.156, 0.078, and 0.039%) of BA and BB for 30 s. Then, the treated filter papers were placed one by one in several Petri dishes and allowed to air dry for two to three minutes. Adults of T. castaneum were then successively released into the Petri dish. Acetone-soaked filter paper was used as a control. Each treatment was carried out in five replicates, each with 20 adult insects. All treatments were kept in an incubator at 28 ± 2 °C with a humidity of 70 ± 5 RH. After 24 h following their release, the insects were softly stroked with a hairbrush to determine whether they were still alive. If the insect did not respond, it was considered dead.