Phoenix dactylifera L. (Arecaceae) seed as a source for insecticide candidates against the mosquito Culex pipiens L. (Diptera: Culicidae)

Abstract The intensive use of synthetic chemical insecticides to control mosquitoes has led to the emergence of insecticide resistance; consequently, eco-friendly botanical insecticides have been screened for use as alternatives to chemical insecticides. Only a limited number of reports are available regarding the production of green biopesticides from fruit seed waste. Hence, this study aims to determine the insecticidal activity of five fruit seed extracts against the Culex pipiens mosquito. Methanolic extracts of apricot ( Prunus armeniaca ) , plum ( Prunus domestica ) (Rosaceae), olive ( Olea europaea ) (Oleaceae), Egyptian doum ( Hyphaene thebaica ) , and date palm ( Phoenix dactylifera ) (Arecaceae) seeds were tested against Cx. pipiens third-instar larvae. The extract of the date P. dactylifera seeds was selected for phytochemical screening and fractionation. The fractions were tested against Cx. pipiens larvae; subsequently, the LC 50 values of the most effective fraction were determined against the third-instar larvae and adult females. The petroleum ether fraction 's LC 50 value was further tested against eggs and different larval instars. Later, this fraction was analyzed using LC‒ESI‒MS/MS. The results showed that P. dactylifera seed extract exhibited the highest mortality rate, followed by P. armeniaca and H. thebaica . The petroleum ether fraction caused higher mortality than the other fractions tested. The LC 50 values for the third-instar larvae and adult females were 43.7 and 4381.2 mg/L, respectively. The early instars were more susceptible than the later instars of Cx. pipiens . Gamma-linolenic acid and hinokitiol were identified as the major compounds, followed in abundance by apigenin, glycerol-2-phosphate, and dihydrocapsaicin. P. dactylifera seed extract demonstrated promising larvicidal activity, particularly in its petroleum ether fraction, highlighting its potential as a cost-effective and environmentally friendly candidate for mosquito control. However, its comparatively lower efficacy against adult mosquitoes indicates that further studies are needed to optimize its application and evaluate its practical use in integrated vector management.