Publication Type
Journal Article
Journal Name
Journal of Agriculture and Food Research
Publication Date
2-1-2026
Abstract
The past decades have witnessed a dramatic re-emergence of lepidopteran pests threatening global food security, yet their control remains heavily reliant on synthetic pesticides, posing persistent risks to human health and ecosystem integrity. We assess the pest control effects of insect oil-based biorationals as an eco-friendly alternative against invasive, Phthorimaea absoulta [i.e., formerly Tuta absoluta ] and Spodoptera frugiperda , focusing on its ovicidal, larvicidal, translaminar, and oviposition-repellent effects. Oil-based biorationals were prepared by mixing black soldier fly (BSF) frass extract with varying rates of insect (BSF) oil and neem oil (25, 50, and 100 μL mL−1) and applied under semi-field conditions in a screenhouse. No significant difference was observed between insect oil- and neem oil-based biorationals. Ovicidal bioassays showed moderate suppression of P. absoluta (20.0–55.3 %) and S. frugiperda (6.7–56.5 %), while contact and ingestion assays induced higher larval mortalities of 33.8–92.9 % and 10.6–93.8 %, respectively, with efficacy increasing at higher concentrations. Notably, insect oil-based biorationals achieved 50 % larval mortality (LC50) in P. absoluta at concentrations as low as 4.9–11.4 μL mL−1, whereas higher concentrations of 29.8–32.3 μL mL−1 were required to achieve the same effect in S. frugiperda . Translaminar exposures also recorded moderate to high mortalities in both species. Treated crops exhibited significant oviposition deterrence, with egg deposition reduced by 3–7-fold for P. absoluta and 1–16-fold for S. frugiperda. Larval mortality and phytotoxicity increased with oil concentration, with peak phytotoxicity recorded at 100 μL mL−1. These results indicate that insect oil-based biorationals holds potential for integration into pest management programs targeting invasive lepidopteran pests, however, further validation under field conditions is warranted.
Keywords
Biorational pest control, Black soldier fly frass, BSF oil, Essential oils, Neem oil, Phthorimaea absoluta, Spodoptera frugiperda
Recommended Citation
Tanga, C., Onyango, L., Malusi, P., Subramanian, S., Tenkouano, A., & Beesigamukama, D. (2026). Insect oil-based biorationals as novel alternative against the invasive tomato leafminer [Phthorimaea absoluta] and fall armyworm [Spodoptera frugiperda]. Journal of Agriculture and Food Research, 25 https://doi.org/10.1016/j.jafr.2025.102583