Investigation of the Detectability of Corn Smut Fungus (Ustilago maydis DC. Corda) Infection Based on UAV Multispectral Technology

Abstract

Corn smut fungus (Ustilago maydis [DC.] Corda) is a globally widespread pathogen affecting both forage and sweet maize hybrids, with higher significance in sweet maize. Remote sensing technologies demonstrated favorable results for disease monitoring on the field scale. The study focused on the changes in vegetation index (VI) values influenced by the pathogen. In this study, four hybrids, two forage maize and two sweet maize hybrids were examined. Artificial infection was carried out at three different doses: a low (2500 sporidium number/mL), medium (5000 sporidium number/mL) and high dose (10,000 sporidium number/mL) with a non-infected control plot for each hybrid. The experimental plots were monitored using a multispectral UAV sensor of five monochrome channels on three different dates, i.e., 7, 14 and 21 days after infection. Five different indices (NDVI, GNDVI, ENDVI, LCI, and NDRE) were determined in Quantum GIS 3.20. The obtained results demonstrated that the infection had a significant effect on the VI values in sweet maize hybrids. A high-dose infection in the Dessert R 73 hybrid resulted in significantly lower values compared to the non-infected hybrids in three indices (NDVI, LCI and GNDVI). In the case of the NOA hybrids, GNDVI and ENDVI were able to show significant differences between the values of the infection levels.

The Effect of Ustilago maydis and Delayed Harvesting on A- and B-Type Trichothecene Concentrations in Maize Grain

“…Nevertheless, the degree of infection is also influenced by hybrid resistance to specific pathogens. The research conducted in Hungary indicated that common smut infection exhibits divergent effects on various maize hybrids, particularly emphasizing the higher impact on sweet maize hybrids [ 10 ]. Therefore, developing hybrids that are resistant to pathogens through breeding or genetic engineering is crucial to establishing a foundation for sustainable agriculture [ 12 ].…”

“…The findings from researchers in China suggest that the resistance to maize common smut may be attributed to intricate gene co-expression and metabolism networks associated with amino acids and reactive oxygen species metabolism [ 10 ]. German research demonstrates that breeding or engineering maize hybrids with enhanced resistance, specifically targeting the susceptibility factor lipoxygenase 3 through gene-editing techniques, holds promise for reducing disease symptoms and fungal infections caused by U. maydis [ 12 ].…”

“…Considering the varying degrees of resistance exhibited among different maize hybrids, it is recommended to prioritize the selection of less susceptible hybrids to effectively protect the crop [ 10 ]. Resistance to U. maydis is believed to be a quantitative trait influenced by multiple minor gene effects.…”