Allelopathic Effects of Chromolaena Odorata L. (R. M. King and Robinson – (Awolowo Plant’)) Toxin on Tomatoes (Lycopersicum esculentum Mill)

Abstract

Allelopathic effects of Chromolaena odorata L. (R. M. KING AND ROBINSON) aqueous leaf extract and residues incorporated in the soil on the growth and water status of Lycopersicon esculentum Mill were studied. Significant growth reductions in Lycopersicon esculentum were observed from additions of C. odorata aqueous – leaf extract at concentrations as low as 1g fresh weight in 40ml of water. Reduction in growth was accompanied by decreases in leaf water potential. Incorporation of C. odorata leaf material into the soil in which L esculentum Mill seedlings were germinated and grown caused significant depression in growth over the 2-week test period with addition of 2g residue to 80g soil. Allelochemicals released from C. odorata plants and residue are suggested as a possible explanation for yield reductions in crops in fields where C. odorata plants are present. One mechanism of toxic action on seedlings involved interference with water balance