Fungicide Effects on Mycotoxins and Forage Quality on a Brown Midrib and a Dual-Purpose Silage Corn Hybrid

Silage corn(Zea mays L.) is an important forage crop in Michigan and across the United States. Brown midrib (BMR) and dual-purpose corn hybrids are commonly used, where dual-purpose hybrids can be harvested for silage or grain and BMR have a more desirable nutritional profile at the cost of being susceptible to disease. This study investigated how these two silage types respond to eight different fungicide products, comparing their efficacy in suppressing foliar pathogens, reducing mycotoxin accumulation, and influencing the hybrid's yield and nutritional profile. Field trials were conducted at two Michigan locations in both 2022 and 2023. Results from the trial revealed significant differences primarily in the BMR hybrid. In the BMR hybrid, fungicide product resulted in differences in mycotoxin concentrations; zearalenone (P < 0.05) and deoxynivalenol (P < 0.05), lignin percentage of dry matter (P < 0.01), estimated milk production, expressed as kilograms of milk per metric ton of silage (P < 0.05) and per hectare of silage (P < 0.05). Dry tonnage yield, foliar tar spot disease index, and all other nutrient parameters investigated were not significantly different between fungicides on the BMR. The only significant difference between fungicide treatments in the dual-purpose trial was found in zearalenone concentration (P < 0.05). Across all 288 samples, T-2 toxin was detected in 14 samples, and aflatoxin was not detected. Samples were not tested for fumonisin. Findings of this study offer insight into how BMR and dual-purpose silage types respond to different fungicides, supporting informed management decisions.