Biological seed treatments using entomopathogenic fungi for enhanced insect pest control

Overview

This research addresses a critical barrier to commercial adoption of entomopathogenic fungi (EPF) as biological seed treatments for insect pest control. Metarhizium and Beauveria are naturally occurring insect-killing fungi with significant potential as sustainable alternatives to chemical pesticides, but their sensitivity to hydration and dehydration has historically caused rapid loss of spore viability, limiting practical use. The proposed solution combines dry powder and emulsified oil formulations with conventional water-based seed coating processes, enabling co-application with standard seed treatments while protecting fungal spores. The result is improved loading capacity, application uniformity, and extended shelf life—key factors for integrating biological controls into mainstream seed treatment workflows in row crops and turfgrass.

Technical specifications

Core technology:

• Entomopathogenic fungi strains including Metarhizium anisopliae strain ESF1 and Beauveria bassiana strain GHA
• Dry seed coating formulations using talc/graphite mixtures and high-density combinations of barium sulfate with bentonite, calcium carbonate, or calcium sulfate
• Emulsified oil formulations developed as standalone or co-applied treatments
• Water activity (aw) equilibration to 0.3, identified as optimal for EPF spore stability
• Fluorescent tracer methodology for assessing application uniformity on seed surfaces
• Rotary pan coater application process using aqueous binder with concurrent dry EPF powder application
• Chemical additives to reduce osmotic or matric potential and minimize fungal exposure to water

Key performance findings:

• Metarhizium viability maintained across all tested dry seed coating formulations
• Talc/graphite mixtures did not reduce germination in two turfgrass species
• Formulations compatible with conventional water-based seed treatment infrastructure

Applications:

• Turfgrass insect pest management
• Row crop seed treatment for early-season insect control
• Integrated pest management programs seeking biological alternatives

Technology readiness level

The technology is currently at Technology Readiness Level (TRL) 4–5, having completed laboratory validation of formulation stability and seed germination compatibility. Initial proof-of-concept work has demonstrated that dry coating formulations preserve Metarhizium viability and do not impair turfgrass seed germination. Future validation will include accelerated shelf-life testing (aging treated seeds for 7 to 28 days at 40°C), quantitative conidial viability assays following equilibration to optimal water activity, and refinement of coating processes to further minimize EPF exposure to water. The research leverages established cooperators across formulation chemistry, turfgrass entomology, and field crop pathology, positioning the technology for advancement toward field trials and commercial scale-up.