Efficacy of Biorational Spray Schedules for Sustainable Management of Citrus Thrips (Scirtothrips dorsalis Hood) in Acid Lime

Abstract— Citrus thrips (Scirtothrips dorsalis Hood) is a major constraint in acid lime production, causing leaf distortion, flower drop and severe fruit scarring. Excessive reliance on synthetic insecticides has led to resistance development, residue concerns and disruption of natural enemies. Field experiments were conducted during 2022–23 and 2023–24 at Citrus Research Station, Petlur, Tirupati (Dt), Andhra Pradesh, India to evaluate the efficacy of different biorational insecticide spray schedules against citrus thrips. Eight treatments comprising neem-based botanicals, horticultural mineral oil (HMO), entomopathogenic fungi and Spinosad were evaluated in a randomized block design with three replications. Two sequential sprays were applied at petal fall and pea-size fruit stages. Treatments involving HMO @ 10 ml/lit followed by Spinosad 48 SC @ 0.25 ml/lit and Azadirachtin 1% EC (2 ml/lit) followed by Spinosad 48 SC @ 0.25 ml/lit recorded the lowest thrips population, minimum fruit infestation (3.6–4.1%) and highest yield (20.9–22.4 t/ha) across both seasons. Entomopathogenic fungi provided moderate but significant control, whereas mineral oil alone was less effective under higher pest pressure. The study clearly demonstrates that rotation of biorational insecticides with different modes of action ensures effective suppression of citrus thrips, reduces fruit damage and enhances yield. Such biorational spray schedules offer an environmentally safe, residue-free and sustainable alternative to conventional insecticides and can be effectively integrated into IPM programmes for acid lime cultivation.