Indigenous Entomopathogenic Nematodes: A Standardized Semi-Field Protocol for Assessing Biocontrol Efficacy and...

The aim of this study was to develop a standardized, stepwise protocol for assessing the efficacy and persistence of entomopathogenic nematodes (EPNs) under realistic field conditions. Research on indigenous EPNs in developing countries has predominantly focused on laboratory-based evaluations, with limited assessment under natural field conditions. This article provides a standardized semi-field approach that bridges the gap between controlled laboratory bioassays and large-scale field evaluations. It involves confining the target pest, false codling moth larvae, within experimental units (cages), allowing controlled exposure to EPNs while maintaining natural environmental conditions. This approach enables the assessment of both immediate biocontrol efficacy and longer-term persistence of EPN activity in soil. The experimental design, statistical framework, and standardized procedures for laboratory trials, baseline sampling, cage placement, handling, EPN application, and monitoring are described. The sequential workflow begins with laboratory-derived information and progresses to field application, followed by assessment of infective juvenile activity and persistence in soil over time. A published study on false codling moth larvae is presented as a case study to demonstrate the successful application of the protocol and its ability to quantify EPN performance under natural field conditions. The protocol forms part of a sequential evaluation framework in which promising indigenous EPN candidates progress from laboratory screening to semi-field assessment before large-scale field evaluation. The resulting data can be used to identify effective EPN isolates and determine their short- and long-term biological control potential and suitability for further development. © 2026 Wiley Periodicals LLC. Basic Protocol 1: Laboratory bioassays Basic Protocol 2: Field trial layout Basic Protocol 3: Baseline sampling for resident EPNs Basic Protocol 4: Preparation of insect containment cages Basic Protocol 5: Application of EPNs Basic Protocol 6: Evaluation of EPN control Basic Protocol 7: Persistence of EPN efficacy.