Optimal Irradiation Strategy to Induce Male Sterility in Cotton Mealybug, Phenacoccus solenopsis Tinsley (Hemiptera: Pseudococcidae)

<i>Phenacoccus solenopsis</i> Tinsley is a highly invasive pest threatening global cotton production and numerous cultivated crops. The sterile insect technique (SIT), based on γ-ray irradiation, offers a sustainable and eco-friendly alternative to chemical controls for managing pests. This study aimed to determine the optimal developmental stage and radiation dose to induce sterility in <i>P. solenopsis</i>. Male pupae aged 5 days demonstrated the highest tolerance to irradiation among all tested age groups. These 5-day-old male pupae were irradiated with 20, 40, 60, and 100 Gy and mated with unirradiated females, and the effects on mating rate, oviposition stage, egg number, egg hatchability, male adult lifespan, and female sex ratio were assessed. Sterility was effectively induced by 60 Gy in males without compromising their mating competitiveness in the parental (F₀) generation. Moreover, sterility traits were inherited by descendants, leading to a progressive decline in population size across the F₁ and F₂ generations. Therefore, a 60 Gy dose was identified as optimal for suppressing <i>P. solenopsis</i> in field settings. These findings establish a theoretical foundation for implementing SIT as a regional pest management strategy for <i>P. solenopsis</i>.