Enhanced insecticidal efficacy of nanoencapsulated bergamot essential oil against stored-product pest Tribolium castaneum (Herbst)

Abstract In this study, bergamot essential oil (BEO) was encapsulated within β-cyclodextrin/gum Arabic (BEO–βCD/GA) to enhance its physicochemical properties and its toxicity against Tribolium castaneum , a major stored-product pest. Gas chromatography–mass spectrometry detected D-limonene (59.38%) as the predominant component of BEO. The optimized BEO–βCD/GA exhibited a particle size of 194.26 ± 2.45 nm, a low polydispersity index (0.04 ± 0.003), zeta potential of − 31.23 mV, and a high encapsulation efficiency of 88.12%, indicating a homogeneous system. BEO–βCD/GA showed greater toxicity than BEO, producing lower LC values and higher T. castaneum mortality across concentrations and exposure periods. The carrier substances showed no toxicity to T. castaneum , confirming that the observed effects were due to BEO or BEO–βCD/GA. The LC 50 and LC 90 values of BEO–βCD/GA were consistently lower than those of BEO across all exposure periods (1–7 days). At 7 days, BEO–βCD/GA recorded markedly lower LC 50 (106.85 ppm; 3.15–173.54) and LC 90 (319.49 ppm; 200.18–4468.97) compared with BEO (LC 50 : 437.72 ppm: 359.29–596.06; LC 90 : 3195.87 ppm: 1710.83–10801.66). The BEO–βCD/GA achieved near-complete inhibition of progeny emergence (97–100%) at higher concentrations, compared to 61–79% for BEO. In addition, BEO–βCD/GA significantly reduced grain weight loss and exhibited strong antifeedant activity. Neither treatment adversely affected wheat germination nor seedling vigor. These physicochemical characteristics, together with the formulation’s enhanced insecticidal performance, suggest improved stability and bioavailability of BEO within the βCD/GA system, making it a promising, eco-friendly alternative for sustainable stored-product pest management.