Durable Suppression of G. pallida via Masculinizing Resistance, Rotation & Biocontrol: Insights from a Stochastic Model with Genetic Drift

The pale cyst nematode, Globodera pallida, threatens potato crops worldwide. With effective nematicides banned due to toxicity, alternative control strategies are needed. However, crop rotation and biocontrol have limitations, and resistant cultivars are vulnerable to virulent nematode evolution. Masculinizing resistance, which prevents avirulent nematodes from producing females, may offer more durable control than blocking resistance. Our stochastic demo-genetic model, accounting for genetic drift, suggests that virulence against masculinizing resistance may not fix in nematode populations under realistic conditions. Avirulent males can transmit avirulent alleles by mating with virulent females, maintaining avirulence despite widespread resistance. Moreover, avirulent nematodes reduce population density by at least 20% and may even cause collapse. The probability of nematode extinction decreases sharply as the initial virulence allele frequency rises, highlighting the need for molecular tools to monitor virulence in the field. Our model suggests that combining masculinizing resistance with rotation and biocontrol could sustainably suppress G. pallida. To aid implementation, we provide an interactive online tool for growers, plant health authorities, and researchers to test control strategies.