Development of ant-based mutualistic and antagonistic biocontrol strategies against cotton mealybugs

The cotton mealybug Phenacoccus solenopsis Tinsley, an invasive pest, has posed a significant threat to Bangladesh's cotton industry, with conventional insecticides proving ineffective against this pest and ecologically detrimental. This research aimed at biocontrol of cotton pest focusing mainly on mealybug in four colored cotton lines (BC 111, BC 113, BC 119, BC 120). The experiment involved seven treatments, incorporating both naturally and artificially colonized mealybugs, ants, and cotton bollworms, arranged in a factorial randomized complete block design with three replications. This study revealed significant variations in pest dynamics and plant health across different treatments and genotypes. Notably, the treatment comprising of natural mealybug infestation with the presence of induced cotton bollworms and ants was the most effective at minimizing mealy bug population in cotton. Among the ant species identified, Tapinoma simrothi Krausse and Monomorium libanicum Lebanese Monomorium exhibited considerable efficacy in biocontrol of mealybug (32.16) under induced conditions, reducing plant damage to 8.0% and 12.41%, respectively. The mutualistic behavior of M. libanicum with mealybugs, contrasted with the slightly antagonistic associations between the Mealybug and T. caespitam, highlights its potential as a biocontrol agent. Additionally, the cotton genotypes BC 119 and BC 120 exhibited enhanced resistance to pest infestations, with infestation rates of 44.90 and 39.57%, respectively indicating their suitability for breeding programs aimed at improving pest resistance. Furthermore, the significant impact of different treatments on the abundance of ant species highlights the complex interactions between treatments and biocontrol agents, emphasizing the importance of controlling biodiversity and ecosystem processes to ensure the effective deployment and ecological viability of biological control agents. In this research, integrating ant behavior into pest management offers a sustainable alternative to chemical pesticides, potentially boosting cotton productivity and supporting Bangladesh's agricultural sustainability and optimizes the environmental advantages.