Résumé:
The objective of this study was to evaluate the insecticidal effect of hydromethaneic extracts of the dried leaves of Nerium oleander L. and Argania spinosa L., harvested in Mostaganem, against the green rose aphid "Macrosiphum rosae" and the linden bug "Oxycarenus lavaterae." Corrected mortality was calculated after 24, 48, and 72 hours.
The leaves of Argania spinosa L. are characterized by higher moisture content than those of Nerium oleander L., while the extract of the latter species is rich in chlorophyll pigment and has the highest extraction yield.
The aphid showed greater sensitivity to both extracts compared to O. lavaterae, particularly at low doses and during shorter exposure periods. For example, its mortality reached 100% with a 60% dose of Argan extract after 72 hours, while O. lavaterae required higher doses and/or exposure times to achieve similar mortality, reaching 100% at the 100% dose for both extracts after 72 hours. LD50, after 48h of exposure to the treatment, O. lavaterae was weakly affected by both Nerium oleander and A. spinosa extracts, where the LD50 was very high at 87% and 93%, respectively. While the M. rosae population requires lower doses of N. oleander and A. spinosa extract at 36% and 40%, respectively.
This bioinsecticide effect is mainly due to the presence of flavonoids, saponins, tannins, terpenoids, reducing compounds, and mucilages in both extracts. Free alkaloids and quinones were present only in N. oleander L.
