Optimal irradiation parameters for the development of the sterile insect technique in the seedcorn maggot Delia platura (Diptera: Anthomyiidae)

BACKGROUND: The seedcorn maggot, Delia platura Meigen (Diptera: Anthomyiidae), is a sporadic but economically important pest of vegetables and field crops. In the context of the phase-out of key insecticides, the sterile insect technique (SIT) represents an excellent alternative, but its implementation requires the determination of irradiation conditions that induce high sterility without compromising male quality. We evaluated the combined effects of X-ray dose (20-40 Gy) and pupal age (6-12 days) on emergence, male deformities, induced sterility, and male mating competitiveness in D. platura. RESULTS: Our results show that X-ray irradiation between 20 and 40 Gy induced >98% sterility in males, while emergence remained high and deformities were minimal when treatment was applied at later pupal ages. The interaction between dose and developmental stage affected male competitiveness, with males irradiated at 20 Gy exhibiting mating performance exceeding that of non-irradiated males, regardless of pupal age at irradiation. CONCLUSION: These findings identify 20 Gy as an operationally optimal dose for SIT, balancing high sterility with high male quality. This work provides the first baseline parameters for SIT development against D. platura in North America. © 2026 The Author(s). Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.