Applying Tebuconazole at Different Growth Periods of Peanut Influences Its Efficacy and Persistence

ABSTRACT Peanut is a major oilseed crop widely grown worldwide in tropical and subtropical regions. Disease occurrence poses a major threat to peanut cultivation. Among the biotic stresses, foliar fungal diseases, namely late leaf spot (LLS) and rust, caused by Nothopassalora personata and Puccinia arachidis , respectively, are destructive diseases of peanut and can account for more than 70% yield loss. Though various fungicides, including tebuconazole, are used to manage foliar diseases in peanut, there is no detailed study on the efficacy of tebuconazole applied at different growth periods of peanut in managing foliar diseases and its persistence. Hence, field experiments were conducted for managing foliar diseases of peanut using tebuconazole 25.9 EC at 125 g a.i./ha, applied at various days after sowing (DAS). The best results were obtained in terms of disease management (64.8% reduction in LLS and 58.5% reduction in rust), pod yield (2.40 t/ha) and haulm yield (2.72 t/ha) by applying tebuconazole at 60 DAS. A sample preparation method based on acetonitrile extraction and estimation by liquid chromatography tandem mass spectrometry (LC‐MS/MS) multiple reaction monitoring (MRM) was validated in peanut kernel at 0.01 mg/kg, and dissipation studies were conducted in the field at 125 g a.i./ha. The tebuconazole residues were below the European Union maximum residue limits (EU‐MRLs) on all the sampling days, and the risk quotient was less than 1. This study ensures the safe use of tebuconazole fungicide in peanut production.