Efficacy, food safety and microbial modulation of prothioconazole in the control of peanut pod rot

Abstract BACKGROUND Peanut, a globally cultivated oilseed crop of significant economic value, faces substantial yield losses due to pod rot disease caused by Fusarium solani . We preliminarily found that prothioconazole had great inhibition activity against F. solani. This study aims to further comprehensively evaluate the application potential of prothioconazole for the control of peanut pod rot from in vitro sensitivity, efficacy, food safety and microbial modulation. RESULTS Prothioconazole exhibited great antifungal activity against the mycelial growth of F. solani by inhibiting the biosynthesis of ergosterol. The mean EC 50 value of prothioconazole against 132 F. solani isolates was 1.35 ± 0.11 mg L −1 . The protective efficacy of prothioconazole was higher than curative efficacy on detached peanut pods. Seed dressing with prothioconazole showed great antifungal activity against F. solani and was relatively safe on the germination and emergence of peanuts. However, prothioconazole applied by seed dressing was ineffective in the field. In comparison, spraying of prothioconazole at 720 g a.i./ha on the soil surface around peanut plants three times every 14 days from pegging until full seed could effectively control peanut pod rot (efficacy of 77.04% and 87.49% in 2023 and 2024, respectively) and increased the peanut yield (by 28.03% and 37.21% in 2023 and 2024, respectively). At harvest, the terminal residues of prothioconazole and its metabolite prothioconazole‐desthio in soil, shells and kernels of peanuts were below the maximum residue limit (MRL, 0.02 mg/kg), suggesting a low risk to the environment and humans. At the same time, prothioconazole increased the abundance of bacteria and actinomycetes and decreased the number of fungi. CONCLUSION Overall, due to the high bioactivity, efficacy and safety, prothioconazole has a promising application prospect in controlling Fusarium pod rot. © 2025 Society of Chemical Industry.