Botanical Acaricides for Sustainable Management of Two-Spotted Spider Mite (Tetranychus urticae Koch) in Okra: Current Status and Future Perspectives

Abstract

The two-spotted spider mite, Tetranychus urticae Koch, has become an important constraint in okra cultivation due to its ability to multiply rapidly and cause serious damage to foliage. Infestation often results in reduced photosynthetic activity, poor plant vigour, and significant losses in yield and marketable quality, particularly under warm and dry conditions. Continuous reliance on synthetic acaricides has resulted in several challenges, including resistance development, pesticide residues, resurgence of pest populations, and adverse effects on beneficial organisms. These concerns have encouraged researchers to explore environmentally safer alternatives for mite management. This review critically examines published information on plant-derived acaricides and their potential role in managing T. urticae in okra-based production systems. Findings from studies conducted in India and other countries indicate that neem-based products, garlic-chilli extracts, karanja oil, tulsi extracts, and several essential oils possess significant acaricidal, repellent, and growth-regulating properties. Evidence generated from field investigations conducted under the doctoral research programme of Singh at Banaras Hindu University, Varanasi, indicated that NSKE 5%, azadirachtin 0.03%, and neem oil were among the most promising botanical options for suppressing Tetranychus urticae populations under field conditions. Unlike many conventional acaricides that primarily target a single physiological pathway, botanical products influence mite populations through several complementary mechanisms, including direct toxicity, feeding inhibition, reproductive suppression, interference with growth and development, reduction in fecundity, and oviposition deterrence. Their comparatively lower toxicity to natural enemies enhances their suitability for incorporation into integrated pest management programmes. Although several promising results have been reported, challenges related to formulation standardisation, field persistence, and large-scale adoption still need to be addressed. Future efforts should focus on improving formulation technology, validating performance across diverse agro-climatic conditions, and promoting farmer awareness. Overall, botanical acaricides offer a promising component of sustainable and residue-conscious mite management strategies in okra cultivation.