Bioherbicide Formulation Engineering: Advances in Delivery Systems, Stability and Field Performance

Abstract

Bioherbicides offer complementary tools for integrated weed management, but variable field efficacy, limited storage stability and application-system incompatibility continue to restrict adoption. This critical narrative review examines formulation engineering as an integrated development process linking biological active ingredients, carrier architecture, critical quality attributes and field delivery. Conventional aqueous suspensions, grain carriers, alginate and Pesta granules, oil-based and multiple emulsions are compared with biodegradable polymer systems, micro- and nanoencapsulation, cell-free fermentation products, multi-component formulations and precision application. Emphasis is placed on the mechanisms by which formulations influence moisture retention, ultraviolet tolerance, adhesion, rainfastness, release, biological potency and spray performance. Evidence is differentiated by laboratory, greenhouse, field and commercial context; findings from conventional herbicides and other biological crop-protection agents are treated as transferable formulation principles rather than direct proof of bioherbicide efficacy. Cell-free systems avoid the requirement to maintain propagule viability but introduce challenges in chemical characterization, potency standardization and degradation control. Advanced carriers and precision delivery are promising when they address measurable product limitations, although evidence for sustained field advantages remains uneven. We propose a stage-gated, dose-normalized reporting framework integrating active production, formulation, packaging, application, safety and cost per treated hectare. Comparative multi-environment field trials, realistic stability programs and validated potency measures are priorities for translating formulation advances into reliable weed control.