Insecticidal effect of furanocoumarins from fruits of Angelica archangelica L. against larvae Spodoptera littoralis Boisd.

The essential oil (EO) and extracts (EXs) obtained from the seeds of Angelica archangelica were used to determine the efficacy in terms of chronic and acute toxicity, antifeedancy and growth inhibition of Spodoptera littoralis larvae. The EO and the EXs were analyzed by GC/MS and HPLC. The EO contained β-phellandrene as the major substance (60%). Furanocoumarins were identified in the EXs obtained using organic solvents, with the majority content of imperatorin (50–56%). Their varying efficacy was caused by the different composition of the EO and EXs obtained. Significant acute toxicity was caused only by the EO (LD50 96 μg/larva). Significantly higher chronic toxicity was found for the EXs obtained using organic solvents (LD50 was estimated at 0.32, 0.82 and 0.52 mg g−1 for benzene, acetone and methanol, respectively), compared to the EO (LD50 7.53 mg g−1). All the tested EXs and the EO caused growth inhibition. The highest larval growth inhibition was caused by the benzene extract, with ED50 estimated at 2.4 μg g−1. All EXs and the EO also showed antifeedant activity. However, the benzene extract showed the highest efficacy (ED50 0.31 μg cm−2), while the least efficacy was shown by the water extract (ED50 1.92 μg cm−2). In order to determine the dependence of biological efficacy of the EXs, LD50 and ED50 values were subjected to regression and correlation analysis. The analysis showed dependence between the total content of furanocoumarins in the extracts and chronic toxicity (R2 = 0.8451; P < 0.01) or larval growth inhibition (R2 = 0.8941; P < 0.01). This dependence was also confirmed for all individual furanocoumarins except bergapten, which showed no dependence.Based on a comparison of the determined efficacy and yield of the extracts, extracts from A. archangelica seeds obtained using methanol can be recommended as suitable for the development of botanical insecticides against S. littoralis larvae.

► The toxicity, antifeedancy and growth inhibition were determined. ► The essential oil contained β-phellandrene as the major substance. ► The furanocoumarins were identified in the extracts. ► The dependence between the furanocoumarins and toxicity or larval growth inhibition was identified.