The bio-herbicidal potentials of aqueous extracts of the leaves and barks of Azadirachta indica (A. Juss.) were investigated. The extracts from leaf and bark of A. indica inhibited the germination and seedling growth of Bidens pilosa L. The degree of inhibition demonstrated in both extracts was concentration dependent. However, the results obtained revealed that the inhibition was more pronounced in the extracts derived from A. indica leaves, as no germination and radicle length emerged until 96hrs experimental time. Similarly, the radicle length in A. indica leaf extract treated seeds reduced from 0.17cm in 3g/200mL concentration to 0.07cm in 15g/200mL extract concentration at 168hrs experimental time. In A. indica bark treated seeds, the radicle length was 0.48cm in 3g/200mL which reduced to 0.17cm in 15mL/200g concentration at 168 hrs. Statistical analysis (ANOVA, P < 0.05) revealed that there were significant differences in the germination, growth of radicle and plumule lengths of the extracts treated seeds when compared to the control experiments. Results obtained on plumule growth were similar to those of radicle in both extracts. This tends to suggest that extracts from A. indica leaves and barks might be useful in the bio-eradication of B. pilosa. Further studies should be carried out to ascertain the potentials of the extracts as bio- herbicides.
Keywords: Azadirachta indica, Bidens pilosa, Gliricidia sepium, aqueous extracts., herbicidal potentials
