Efficacy of Commonly used Insecticides against Sucking Pests on PGPR treated Okra Plants

Okra (Abelmoschus esculentus [L.] Moench), commonly known as bhindi or lady’sfinger, is a widely cultivated vegetable in tropical and subtropical regions globally (Elkhalifa et al., 2021). However, its cultivation faces significant challenges due to pest infestations. In India, okra is commercially grown over approximately 0.53 million hectares, yielding an annual production of 6.46 million tonnes contributing 62% of the global output and playing a vital role in meeting the nation’svegetable demand (Mohapatra et al., 2024). Despite its importance, okra is highly susceptible to various insect pests which include shoot and fruit borers (Earias insulana [Boisd.] and Earias vittella [Fab.]), leafhopper (Amrasca biguttula biguttula [Ishida]), leaf roller (Sylepta derogata Fab.), whitefly (Bemisia tabaci Genn.), aphid (Aphis gossypii Glover), and mite (Tetranychus cinnabarinus Boisduval) (Kodandaram et al., 2017) and yield loss range between 50.00% and 63.41% (Asi et al., 2008 and Mohapatra et al., 2024). Sap-sucking pests like leafhoppers extract chlorophyll, disrupting photosynthesis and causing leaf cupping, yellowing, and bronzing, which slow crop growth. Leafhoppers can cause production losses of 50% to 63.41% (Mohapatra et al., 2024). Aphids, especially A. gossypii, harm young plants, causing stunted growth, wilting, and plant death in severe cases. Their honeydew encourages sooty mold, further blocking photosynthesis and damaging buds, flowers, and fruits (Murovhi et al., 2020; Kedar et al., 2014).

Okra growers opt synthetic insecticides based pest management as a primary strategy (Jan et al., 2022). However, prolonged use of insecticides exerts selection pressure, leading to insecticide resistance in pest populations globally (Cerna et al., 2013; Szczepaniec et al., 2019) and escalates production costs and reduces profitability. In India, okra farmers often apply 10–12 pesticidal sprays in a single growing season-1 to manage sucking pests and fruit borers, resulting in fruits with high pesticide residues, posing serious risks to consumer health (Ounis et al., 2024). Therefore, adopting sustainable practices, particularly Integrated Pest Management (IPM), is imperative for safeguarding both the environment and human health. Plant growth promoting rhizobacteria (PGPR), present a sustainable alternative in agriculture (Santoyo et al., 2021; Harris, 2009) by enhancing plant growth by facilitating nitrogen uptake, phytohormone synthesis, mineral solubilization, andiron chelation (Bowen and Rovira, 1999). PGPR also enhance resistance against pests and pathogens by inducing physical and chemical defenses in plants, a phenomenon termed induced systemic resistance (Kloepper et al., 2004; Nelson, 2004 and Bostock, 2005). This resistance mechanism has been extensively documented in plant–pathogen and plant–insect interactions (Zehnder et al., 2001; Conrath et al., 2006).

PGPR are characterized by their ability to colonize root surfaces, survive and multiply in competitive microbial environments, and express growth-promotion and protection activities (Mohanty et al., 2021; Kloepper and Okon, 1994). About 2–5% of rhizobacteria exert beneficial effects on plant growth when inoculated into soils with competitive microflora (Kloepper, 1978). These bacteria, thriving in the rhizosphere, enhance plant growth via diverse mechanisms (Vocciante et al., 2022; Vessey, 2003). The below-ground colonization of PGPR triggers various biological processes, altering interactions with above-ground herbivores through changes in plant abundance, nutritional quality, and defenses (Hartley and Gange, 2009; Grunseich et al., 2019). Thus, incorporating PGPR into pest management frameworks offers a promising approach to reduce reliance on synthetic pesticides, mitigate environmental hazards, and enhance agricultural sustainability (Basu et al., 2021). This study was conducted to evaluate the efficacy of commonly used insecticides in controlling sucking pests on plants treated with plant-growth-promoting rhizobacteria (PGPR). By integrating PGPR treatment with insecticide use, the study aimed to explore potential improvements in pest management, plant resistance, and overall crop health, providing insights into sustainable pest management strategies.