Novel bacterial bioherbicides for sustainable weed management in cropping systems

Overview

This research program develops novel bioherbicides derived from rhizospheric bacteria as sustainable alternatives for weed management in cropping systems. Prior laboratory discoveries identified bioactive compounds from Lasiodiplodia pseudotheobromae and Pseudomonas aeruginosa, specifically R-3,4-dihydroxy-3-methylisochromen-1-one and 2-(hydroxymethyl) phenol, which demonstrated significant weed control efficacy in greenhouse and field trials across maize and cowpea cropping systems. The program aims to isolate and characterize new bacterial strains, elucidate the structure of their bioactive metabolites, and evaluate herbicidal activity, modes of action, non-target effects, and soil persistence under field conditions.

Technical specifications

Key research activities and capabilities:

• Isolation and screening of rhizosphere-inhabiting bacterial strains for herbicidal activity
• Morphological, biochemical, and molecular characterization using 16S rRNA sequencing
• Structural elucidation of bioactive compounds through TLC, HPLC, FT-IR, LC-MS, 1H NMR, and 13C NMR
• Greenhouse and field evaluation of bioherbicide formulations in maize and cowpea cropping systems
• Non-target effect assessment and host range testing
• Investigation of modes of action and effective delivery mechanisms
• Development of environmentally safe formulation advances
• Soil persistence evaluation at multiple field sites

Technology readiness level

The program has reached an advanced validation stage, with prior bioherbicide formulations (including BH4) having demonstrated significant weed control and improved growth and yield components in maize and cowpea during field trials. Future validation includes isolation of new bacterial strains, molecular characterization, structural elucidation of active compounds, and greenhouse and field trials planned for the 2023 growing season, with final results to be submitted to the funder for validation. The work also includes mentoring postgraduate students as part of ongoing capacity building.