Fungicide program impacts on corn grain fill duration, kernel weight, and grain yield

Abstract

Recent climate variability and emerging diseases have led farmers toward using multiple tactics to protect corn (Zea mays L.) yield, including fungicide applications. Despite observed yield increases from various fungicide application methods in corn, minimal research has addressed the yield component mechanisms driving these gains. Therefore, this research examined how fungicide application methods can impact corn grain fill duration, kernel weight, and grain yield. In 2022 and 2023, a research trial was established in West Lafayette, IN to examine kernel weight accumulation differences between applied fungicide treatments. In addition, two research trials were sampled in Indiana to assess corn harvest kernel number, kernel weight, and yield differences between designated treatments. Examined treatments include the following: (1) nontreated control treatment, (2) subsurface banded fungicide (flutriafol) applied at planting (starter), and (3) foliar fungicide (prothioconazole, trifloxystrobin, and fluopyram) applied at the R1 growth stage. Trial results observed corn grain yield increases at 3 of 6 site-years and 4 of 6 site-years from starter fungicide and R1 foliar fungicide, respectively, when compared to the nontreated due to reduced leaf disease severity. Furthermore, starter fungicide and R1 foliar fungicide increased grain fill duration on average by 3.5 and 4.5 days, respectively, and increased maximum dry kernel weight on average by 5.7% and 9.4%, respectively, across 2022 and 2023. Overall, research data show the ability of various fungicide programs to reduce leaf disease severity, lengthen grain fill duration, and increase final kernel weight, each of which helps explain the yield component mechanisms when foliar diseases are controlled.