Biological activities of essential oil, aqueous and organic extracts of Pituranthos tortuosus (Coss.) Maire

Aqueous and organic extracts, essential oil as well as the powder of Pituranthos tortuosus (Coss.) Maire were tested on the growth of flax (Linum usitatissimum) and turnip (Brassica rapa) to assess its allelopathic potentialities. Besides, biological potentialities of its essential oil were evaluated by estimating its insecticidal (on Cryptolestes ferrugineus and Culex pipiens) and antifungal (on Fusaruim graminearum and Alternaria sp.) activities. Significant growth inhibition of target species was recorded in the presence of the aqueous and acetone extracts, more than 50% in certain cases. P. tortuosus essential oil also induced growth reduction which was almost total in the presence of a concentration of 4000 ppm. In addition, essential oil caused, for C. ferrugineus, a respective mortality of 50% and of 90% at concentrations of 205.68 and 300.37 μl/l air. Otherwise, 50 ppm was sufficient to induce 100% of mortality of C. pipiens larvae, whereas LC50 and LC90 were 15.46 ppm and 23.62 ppm, respectively. A concentration of 4 μl/ml of P. tortuosus essential oil caused a complete inhibition of the mycelial growth of F. graminearum and Alternaria sp. Results show that essential oil as well as organic extracts could be used for the production of natural bio-pesticides which could reduce our dependence on chemical pesticides.

Research highlights▶ Aqueous and organic extracts of P. tortuosus reduced the growth of flax and turnip. ▶ Essential oil and the powder of P. tortuosus inhibited the growth of flax and turnip. ▶ Essential oil had a strong insecticidal effect on C. ferrugineus. ▶ 50 ppm of the essential oil induced 100% of mortality of C. pipiens larvae. ▶ 4 μl/ml of the essential oil caused a complete inhibition of the mycelial growth.