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

TL;DR

This study finds that irradiating 5-day-old male cotton mealybugs with 60 Gy effectively induces sterility, offering a sustainable pest control method.

Contribution

The optimal irradiation dose and developmental stage for inducing male sterility in P. solenopsis are identified for SIT application.

Findings

60 Gy irradiation induced sterility in 5-day-old male pupae without affecting mating competitiveness.

Sterility traits were inherited, leading to reduced population sizes in subsequent generations.

The 60 Gy dose is recommended for field application of SIT to manage P. solenopsis.

Abstract

Phenacoccus solenopsis 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 P. solenopsis. 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 P. solenopsis in field settings. These findings establish a theoretical foundation for implementing SIT as a regional pest management strategy for P. solenopsis.

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