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Sequential application of fungicides with different modes of action for the control of soybean diseases in Canindeyú, Paraguay

2025; Facultad de Ciencias Agropecuarias, Universidad Nacional de Córdoba; Volume: 41; Issue: 2 Linguagem: Inglês

10.31047/1668.298x.v41.n2.44095

1668-298X

Marcos Javier Mendoza-Duarte, Andrea Celeste Zarza-Cabrera, Osmar Arias, Andrea Alejandra Arrúa Alvarenga, Marta Alicia Fernández-Gamarra, Horacio D. Lopez-Nicora, Guillermo Andrés Enciso-Maldonado,

Soybean genetics and cultivation

The study evaluated the impact of fungicide programs (FPs) on disease control in soybean during the 2021/2022 season in La Paloma, Katueté and Nueva Esperanza (Canindeyú, Paraguay). The area under the disease progress curve (AUDPC) was evaluated for the predominant diseases, defoliation, and yield. In addition, the control efficacy (CE) and the reduction in productivity (RP) were calculated. Variance analysis was conducted on factors FP, Location, and their interaction, using Tukey’s test at a 5 % error level for mean comparisons. Target spot (TS) and Cercospora leaf blight (CLB) were the predominant diseases in all locations. Asian soybean rust (ASR) occurred only in Nueva Esperanza and Katueté. FPs reduced AUDPC up to 64, 85 and 73 %, on average, for TS, ASR and CLB, respectively, leading to increased yield, on average, between 9 and 27 %, compared to the control. La Paloma achieved the highest yield (4651 kg ha-1) and lower defoliation (61 %), followed by Katueté (4330 kg ha-1 with 70 % of defoliation), and Nueva Esperanza (3739 kg ha-1 with 86 % of defoliation). This study provides strategies to optimize fungicide use in soybean management in Paraguay, highlighting sequential applications and rotation of modes of action.