Role of PGPR in modulating feeding efficacy, growth and development of Spodoptera litura in Okra

Okra (Abelmoschus esculentus) is an important crop often targeted by Spodoptera litura, a destructive pest that damages the leaves and impairs plant growth, ultimately affecting yield. Plant growth-promoting rhizobacteria (PGPR) have emerged as a promising alternative to chemical pesticides for sustainable pest management. This study evaluated the impact of various PGPR strains, including Bacillus subtilis Bbv57, on the growth and development of S. litura larvae feeding on okra. Controlled laboratory experiments and biochemical analyses were conducted to assess the consumption, digestion and utilization of PGPR-treated plant materials by S. litura. The results showed that PGPR treatments significantly reduced larval consumption and weight gain compared to untreated controls. Additionally, PGPR-treated plants resulted in shorter feeding periods, lower consumption indices, growth rates and conversion efficiencies of ingested and digested food. Faecal output was also reduced in larvae fed on PGPR-treated leaves. These findings suggest that PGPR can enhance plant defence mechanisms, leading to a reduction in pest feeding efficiency. The study highlights the potential of PGPR in inducing systemic resistance and biochemical responses that contribute to pest management. Therefore, this research supports the integration of PGPR in sustainable pest management strategies, offering both environmental and economic benefits in agriculture.