A spatially explicit model simulating western corn rootworm (Coleoptera: Chrysomelidae) adaptation to...

Area of Science:

• Agricultural Entomology
• Population Genetics
• Pest Management

Background:

• Western corn rootworm (Diabrotica virgifera virgifera LeConte) poses a significant threat to maize production.
• Rootworm-resistance traits in maize are crucial for sustainable agriculture.
• Understanding pest adaptation mechanisms is vital for long-term pest control strategies.

Purpose of the Study:

• To develop and utilize a computer model simulating western corn rootworm adaptation to maize resistance traits.
• To compare the efficacy of different non-resistant maize refuge deployment strategies in delaying pest adaptation.
• To assess the impact of crop resistance levels on the durability of resistance traits.

Main Methods:

• A stochastic, spatially explicit computer model was developed to simulate rootworm population dynamics.
• The model incorporated functions for crop development, rootworm mortality, reproduction, and dispersal.
• Simulations compared adaptation allele spread under various refuge scenarios and crop resistance levels.

Main Results:

• In-field block refuges significantly delayed rootworm adaptation compared to scattered refuges.
• Higher doses of insecticidal protein in maize (killing >90% of heterozygotes) resulted in more durable resistance.
• Adult dispersal parameters were identified as key factors influencing adaptation rates.

Conclusions:

• Strategic deployment of non-resistant maize refuges is critical for delaying pest adaptation.
• High-dose expression of insecticidal traits in maize enhances the durability of resistance.
• Computer modeling provides valuable insights for developing sustainable pest management strategies against the western corn rootworm.