Insecticide potency on Alfalfa aphids of Kanuka, Ravintsara and Tea tree essential oils and Neem vegetable oil

Abstract

In the Ziz Tafilalt region in the Southeast of Morocco, alfalfa green is principally cultivated for livestock feed. Aphids cause significant damage to this culture, which pushes farmers to use great quantities of synthetic insecticides during spring and summer. With the objective to reduce damages provoked by aphids on the alfalfa green, while protecting the environ-ment, the insecticidal potency of various essential oils (Kanuka, Ravintsara and Tea tree) and a vegetable oil (Neem) was studied. The mortality of aphids was registered when treating plots by these oils at concentra-tions of 0.25 %, 0.5 %, 1 % and 5 %, and this 1, 3, 5 and 11 hours after treatment. The LC50 and LC90 values indicate a similar activity for the three essential oils and the Neem oil. As may be expected, mortality of the aphids increased with the dose and time after treatment, reaching about 70 % after 11 hours for all products at the different