Mitigating sorghum stalk rot yield loss through foliar and at-planting fungicide applications

Sorghum stalk rot is a worldwide threat to sorghum production. Current management is limited to pre-planting strategies such as hybrid selection and low planting populations. Experiments were conducted at one location in 2023 and three locations in 2024 in Kansas. Treatments included: At-planting, Xyway™ LFR® was applied as a banded dribbled 5.08 cm off-center bellow the row (2x2), a dribbled over the row (0x0), or a dribbled 5.08 cm off the row (0x2) placement. At flowering, Topguard® EQ and Adastrio™ were applied as foliar sprays. A combination treatment of Xyway™ LFR® at planting 2x2, followed by Topguard EQ at flowering was included. Panicle size, lodging, and yield were evaluated. Stalk rot incidence and severity were assessed prior to harvest. Fungicide had no significant effect on protein content, panicle size, disease severity, or disease incidence. Both hybrid type and fungicide application significantly affected grain yield. Overall, applying Xyway™ LFR® at planting 0x0, and using Topguard® EQ and Adastrio™ at the start of flowering, increased yield by 465.98, 484.53, and 505.00 kg ha⁻¹, respectively, compared to the control (p = 0.0003). Foliar application of fungicide at flowering resulted in a greater yield than either at planting application alone or combined at planting and foliar application. These findings indicate that foliar applications at the flowering are the most consistent for maximizing sorghum yield. However, fungicide use did not significantly reduce stalk rot disease in this study.