Effect of Tithonia diversifolia, Alchornea cordifolia, and Mezoneuron benthamianum on Tomato (Lycopersicon esculuntum) Nursery in Daloa (Côte d’Ivoire)

Aims: Research of alternative solutions to the use of synthetic pesticides.

Study Design : Randomized block.

Place and Duration of Study: Jean Lorougnon Guédé University (Daloa, Côte d’Ivoire), January to February 2020.

Methodology: Extracts of Alchornea cordifolia, Tithonia diversifolia and Mezoneuron benthamianum were evaluated in vitro and in the nursery at 5 g/l, 15 g/l and 25 g/l. In vitro, the blotting paper method was used on tomato seed germination. In the nursery, the powdery extracts were added to the nursery soil bags with four treatments (5 g/l, 15 g/l, 25 g/l and control) and six bags per treatment with five tomato seeds per bag. Germination rate, number of leaves, height and the health status of the plants as well as the incidence and severity of root galls were evaluated. The results showed that in vitro the control had the highest average germination rate (98.5%) followed by T. diversifolia (43.03 to 98.5%), A. cordifolia (35.33 to 68.67%) and M. benthamianum (37.66 to 67.55%). However, in the nursery, T. diversifolial recorded the highest average treated seed germination (38 to 78.33%) and seedling emergence (12.78 to 38.33%) rates compared to the other treatments. Concerning growth parameters, the number of leaves (5.38 to 13.21) and height (5.71 to 15.64 cm) of tomato plants were influenced by the extracts type and concentration. The incidence of root galls was low for treated plants (0-60%) compared to controls (100%). The severity of the galls was significantly reduced by the extracts, however the extracts of T. diversifolia were the most effective. Extracts were more effective at low concentrations in improving agromorphological parameters of tomato, in contrast to the incidence and severity of galls which were reduced at high concentrations. Results suggest that these locally available plants could be used as biofertilizers and control method against root-knot nematodes.