Isofuranodiene-based nanoemulsion: larvicidal and adulticidal activity against tenebrionid beetles attacking stored wheat

The resistance of insect populations to the existing insecticides grows fast due to their continuous use. Thus, the need for new and effective formulations is increasing. Isolated compounds of botanical origin may represent a promising solution for green pest management strategies. In this study, isofuranodiene derived from Smyrnium olusatrum L. (Apiales: Apiaceae) essential oil (EO), was nanoemulsified (3% w/w) to treat wheat kernels with two concentrations (500 and 1000 ppm) against adults and larvae of three tenebrionid beetles attacking stored products, the red flour beetle, Tribolium castaneum (Herbst), the confused flour beetle Tribolium confusum Jacquelin du Val, and the yellow mealworm beetle, Tenebrio molitor L. Mortality rates were calculated after 4, 8 and 16 h and 1, 2, 3, 4, 5, 6 and 7 days. The isofuranodiene-based nanoemulsion (NE) exhibited high adulticidal effects against T. molitor, and larvicidal activity against T. castaneum and T. confusum, reaching 98.6, 97.4 and 93.5% at 1000 ppm after 7 days of exposure, respectively. On the other hand, the NE caused low mortality rates on adults of T. castaneum and T. confusum, as well as on larvae of T. molitor, not exceeding 26.2, 10.0 and 15.6% at 1000 ppm, 7 days post-exposure, respectively. Overall, the 3% (w/w) isofuranodiene-based NE developed here has a significant potential to protect stored wheat from tenebrionid beetle infestations.