Effect of Artemisia annua Extracts on Lettuce Cultivation in Saïoua, Ivory Coast

Abstract

Background: Lettuce production in Saïoua is constrained by pest pressure and frequent dependence on synthetic inputs. Aims: This study evaluated the effect of Artemisia annua L. extracts on the growth and yield of lettuce (Lactuca sativa L.) in Saïoua, with the aim of proposing a sustainable agroecological alternative to synthetic chemical pesticides. Study Design: The trial was established on 100 m² using a Fisher block design with 15 experimental units (12 plants per unit). Five treatments, each replicated three times, were compared: untreated control (Tm), aqueous extract of Artemisia annua (Te), Artemisia powder (Po), Artemisia residues (Re), and the chemical insecticide TOP LAMBDA 25 EC (So). Place and Duration of Study: The study was conducted in Saïoua (Châteaux neighbourhood), Ivory Coast. The nursery phase lasted 21 days, followed by field monitoring until harvest (30 days). Methodology: The plants were transplanted at a spacing of 40 cm × 40 cm. Agronomic parameters (number of leaves, height, and spread) and production parameters (yield) were measured and then analysed using ANOVA and the Newman-Keuls and Tukey tests (p < 0.05) in the R software package. Results: The aqueous extract produced the highest observed agronomic values, with 5.12 ± 1.54 leaves/plant, a height of 7.65 cm, and a spread of 9.84 ± 2.85 cm, compared with 2.24 leaves, 3.74 cm, and 5.08 cm for the control. In terms of yield, the aqueous extract recorded the highest observed value (60 g/m²), compared with the chemical insecticide (50 g/m²) and the control (20 g/m²). Strong positive correlations (R = 0.9580–0.9927) were observed among the growth variables. Conclusion: The aqueous extract of Artemisia annua combines biopesticidal and biofertilising properties that stimulate lettuce growth. It represents an effective and environmentally friendly organic alternative for vegetable growers in Saïoua.