The potential effect of banana by-products on the in vitro inhibition of Lasiodiplodia theobromae and Colletotrichum sp

Banana rachis leachate (BRL) is an agricultural by-product rich in phenolic compounds, with potential use as a biofungicide. Lasiodiplodia theobromae and Colletotrichum sp. are pathogens that have developed resistance to conventional fungicides, highlighting the need for alternatives from natural origin. The objective of this research was to evaluate the efficacy of banana rachis leachate in inhibiting the growth of L. theobromae and Colletotrichum sp. and to characterize its chemical properties. The BRL was lyophilized, and characterized to determine its chemical composition (macro and micronutrients), total phenolic content, and Fourier transform infrared spectroscopy (FT-IR) was used to identify functional groups. The BRL inhibitory effect was tested at concentrations of 0.5, 2.5, 5, and 7.5 % on fungal mycelial growth in culture media, monitored over seven days. The BRL showed high concentrations of potassium (7520 mg L⁻¹), phosphorus (131.05 mg L⁻¹), and significant phenolic content (11649.7 μg GAE mL⁻¹). BRL concentrations of 5 % and 7.5 % inhibited fungal growth by up to 80 %. Hyphal deformation was observed, suggesting interference with fungal membrane permeability. BRL is an effective and sustainable biofungicide that significantly inhibits the growth of L. theobromae and Colletotrichum sp., while also providing essential soil nutrients.