Résumé:
This research primarily aims to investigate the insecticidal potential of the essential oil of Eucalyptus camaldulensis against Aphis fabae, a notorious pest affecting broad bean (Vicia faba) crops, whose population has been on the rise in Algeria. To achieve this objective, steam distillation was used to extract the essential oil from the leaves of Eucalyptus camaldulensis, followed by an evaluation of the oil’s toxicity through two types of tests: contact and repellent. A significant yield of essential oil was obtained, estimated at 6.6% from 1500g (0.44% from dried leaves). The results of both tests showed insecticidal activity proportional to the applied doses (0.5; 1; 1.5; and 2 μl/ml) as well as to the exposure times (5, 30, 60, and 120 minutes). A mortality rate of 100% was recorded at 1.5 and 2 μl/ml in the contact test, while the repellent test showed a lethality of 74.75% after 120 minutes of treatment.
For comparison, a reference chemical insecticide, Acetamiprid 20% (Astrad®), was used as a positive control. It also caused 100% mortality in the contact test, but showed low repellent activity in the repellency test.
The eucalyptus essential oil proved to be highly effective even at low doses, with an LD₅₀ of 0.43 μl for the contact test and 0.036 μl for the repellent test. These promising results provide a foundation for the development of natural-origin bio pesticides that can be integrated into biological control strategies.
