Field strength and frequency-dependent effects of pulsed electric fields on soilborne nematodes, pathogens, and weeds

Pulsed electric field (PEF) technology is a non-chemical approach with potential to control soilborne agricultural pests. PEF disrupts cellular membranes through short, high-energy electrical pulses. Treatment efficacy depends on electric field strength, pulse frequency, and applicator design. Field strength reflects the intensity of the electric field driving electroporation, whereas energy density represents the cumulative dose delivered to the system, and pulse frequency determines how that dose is distributed over time. In this study, two soil-applied PEF applicators, vertical pins (VP) and parallel plates (PP), were evaluated for suppression of weeds, plant-parasitic nematodes, and soilborne pathogens. Numerical simulations showed that the PP configuration generated a more uniform electric field distribution than the VP design. Consistent with these predictions, the PP applicator provided greater biological suppression across target organisms. Cyperus esculentus biomass declined progressively with increasing energy density and was significantly reduced at ≥100 J cm^-3. The PP applicator also reduced Meloidogyne chitwoodi second-stage juveniles by up to 100% at 25 J cm^-3 and pulse frequencies above 60 Hz. Densities of Pratylenchus neglectus and M. chitwoodi were reduced by more than 98% at 400 V mm^-1. Weed responses were species dependent: biomass of C. esculentus and Digitaria sanguinalis declined at 100-200 J cm^-3, whereas Echinochloa crus-galli required higher energy inputs for control. Soilborne pathogens also differed in susceptibility, with Phytophthora cinnamomi and P. plurivora reduced by 94% at moderate field strengths (100-200 V mm^-1), while Verticillium dahliae was suppressed by up to 97% at 200-400 V mm^-1 and 80 Hz. Overall, nematodes and soilborne pathogens were suppressed at substantially lower energy densities (~25 J cm^-3) than weed propagules, which generally required ≥100-200 J cm^-3 for effective biomass suppression. These results demonstrate that PEF can effectively suppress multiple soilborne pests. Additionally, the results highlight the importance of applicator design and electrical parameters in determining treatment efficacy, supporting the potential of PEF as a scalable and sustainable soil disinfestation technology.