Study of the interactions between Tetranychus urticae, Phytoseiulus persimilis and Macrolophus pygmaeus in a tomato glasshouse: a cross‐diffusion model case study with Beddington–DeAngelis response

BACKGROUNDThe two‐spotted spider mite (TSSM), Tetranychus urticae Koch, poses a significant threat to greenhouse tomato production, potentially causing ≤40% yield loss. Although biological control using the specialist predator Phytoseiulus persimilis and generalist predator Macrolophus pygmaeus has proven effective in small‐scale studies, their interactions in large commercial glasshouses remain poorly understood. This study develops a mathematical model incorporating spatial dynamics and multispecies interactions to bridge laboratory findings with commercial applications.RESULTSOur model incorporating diffusion patterns, plant defense and intraguild predation best predicted population dynamics (MSE: 0.221, 0.125 for T. urticae and P. persimilis, respectively). Spatial diffusion had the strongest impact on model accuracy, whereas all M. pygmaeus‐induced effects were minimal in practice. The model achieved 77.2% directional accuracy in 3‐week forecasts for T. urticae populations. Simulations revealed that early releases of P. persimilis (0.5 individuals per leaf) could effectively control T. urticae within 4 weeks.CONCLUSIONThis study demonstrates that many species interactions observed in small‐scale experiments may not translate directly to effective biocontrol in commercial settings, which is likely to be a consequence of spatial dilution. We further found that spatial movements outweigh laboratory‐observed effects. Lastly, our model enables 3‐week advance predictions of T. urticae populations and provides evidence‐based guidance for biocontrol agent release strategies, helping growers optimize their pest management decisions. © 2025 Society of Chemical Industry.