Toxicity and repellent effect of essential oils and a major component against Lipaphis erysimi

Abstract

Essential oils (EOs) extracted from aerial parts of Aster indamellus Grierson, Calamintha umbrosa Benth. and Erigeron annuus (L.) Pres. were analyzed by GC, GC/MS. The major acetylenic constituent (cis-lachnophyllum ester) of E. annuus was isolated and characterized by H and C-NMR spectra. Their toxicity and repellent effect against Lipaphis erysimi was tested. Oils of E. annuus and C. umbrosa exhibited higher toxicity on direct spray and by fumigation. LC50 value of E. annuus oil was 0.43 mg/ml as direct spray. By fumigation, LC50 value for E. annuus was 1.29 ml/l air, while for C. umbrosa; it was 1.00 ml/l air. With acetylenic ester, about half of L. erysimi were killed at 10 mg/ml approximately within 13.25 h, while with E. annuus oil the LT50 value was approximately 8.89 h. In conclusion, the EO of E. annuus and its acetylenic constituent have potential as biopesticide for economically important crop pests.