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

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 ۱H and ۱۳C-NMR spectra. Their toxicity and repellent effect against Lipaphiserysimi was tested. Oils of E. annuus and C. umbrosa exhibited higher toxicity on direct spray and by fumigation. LC۵۰ value of E. annuus oil was ۰.۴۳ mg/ml as direct spray. By fumigation, LC۵۰ value for E. annuus was ۱.۲۹ ml/l air, while for C. umbrosa;it was ۱.۰۰ ml/l air. With acetylenic ester, about half of L. erysimi were killed at ۱۰ mg/ml approximately within ۱۳.۲۵ h, while with E. annuus oil the LT۵۰ value was approximately ۸.۸۹ h. In conclusion, the EO of E. annuus and its acetylenic constituent have potential as biopesticide for economically important crop pests.

Keywords:

Essential oil , cis-lachnophyllum ester , Lipaphis erysimi , toxicity , repellence