Assessment of the allelopathic effect of leaf and seed extracts of Canavalia ensiformis as postemergent bioherbicides: A green alternative for sustainable agriculture

• Published in: Journal of environmental science and health. Part B, Pesticides, food contaminants, and agricultural wastes Pesticides, food contaminants, and agricultural wastes, 2014-05, Vol.49 (5), p.374-380
• Main Authors: Mendes, Isequiel Dos S., Rezende, Maria Olímpia Oliveira
• Format: Article
• Language: English
• Subjects: Agricultural and farming systems; Agronomy. Soil science and plant productions; Allelopathic effects; Animal, plant and microbial ecology; Applied ecology; bioherbicides; Biological and medical sciences; Canavalia ensiformis; Chromatography; Commelina benghalensis; Effects; Fundamental and applied biological sciences. Psychology; General agroecology. Agricultural and farming systems. Agricultural development. Rural area planning. Landscaping; General agronomy. Plant production; Generalities. Agricultural and farming systems. Agricultural development; Germination; Glycine max; Herbicides; Ipomoea; Ipomoea grandifolia; Leaves; Legumes; Parasitic plants. Weeds; Phytopathology. Animal pests. Plant and forest protection; Seeds; Sustainable agriculture; weed control; Weeds
• ISSN: 0360-1234; 1532-4109
• DOI: 10.1080/03601234.2014.882179

The herbicidal potential of aqueous extracts prepared from leaves and seeds of Canavalia ensiformis was tested by applying them postemergence to the crop weeds Ipomoea grandifolia and Commelina benghalensis. Considering the possible objective of using this bioherbicide on soybean fields, the extracts were also tested for deleterious effects on both transgenic and conventional soybean (Glycine max). In addition, the concentrations of four phenolic compounds and alkaloids with allelopathic properties in these extracts were estimated by high-performance liquid chromatography. The seed extract at concentrations of 25 g L −1 and 50 g L −1 was the most efficient postemergent bioherbicide. By applying these extracts, the development of the weed seed was progressively hindered until no recovery was observed. The application of 3.5 mL of crude extract on a plant that takes 30 days after germination of the seed to develop is sufficient for full control of the species within 5 days. Since both Ipomoea grandifolia and Commelina benghalensis are broadleaf dicotyledons, it is possible that other species with these characteristics can also be controlled or suffer the same effects under the action of the seed extract, if the same volume and mode of application are used. The selectivity of the treatments with 25 g L −1 and 50 g L −1 was assessed on transgenic and conventional cultivars. The treatments did not visibly affect the soybean cultivars, which developed normally during the observation period that continued up to 15 days after the death of the weeds.