Environmental Drivers of Maize Ear Rots and Mycotoxin Accumulation Across North America

Area of Science:

• Agricultural Science
• Plant Pathology
• Food Safety

Background:

• Maize ear rots, including Gibberella (GER), Fusarium (FER), and Aspergillus (AER), cause significant grain quality issues and mycotoxin contamination.
• FER is linked to fumonisin (FUM), and AER to aflatoxin (AFL), posing health risks.
• Shifting weather patterns necessitate updated assessments of ear rot prevalence and their environmental drivers.

Purpose of the Study:

• To assess current ear rot incidence and mycotoxin accumulation in maize hybrids across North American environments.
• To identify the epidemiological drivers, including environmental conditions and insect damage, influencing GER and FER.
• To inform strategies for managing ear rot and mycotoxin contamination in maize.

Main Methods:

• Screened two maize hybrid panels (108 and 4 hybrids) in replicated trials across diverse North American locations.
• Evaluated ear rot incidence and mycotoxin accumulation (FUM, AFL).
• Correlated disease and toxin levels with environmental data (temperature, moisture) and insect damage.

Main Results:

• Fusarium ear rot (FER) and fumonisin (FUM) were the most prevalent disease and mycotoxin.
• FER predominated in southern regions; GER occurred in northern regions, with FER and FUM also found in northern areas.
• Insect damage correlated with FER and GER; cool, moist conditions favored GER, while warm conditions favored FER and FUM.

Conclusions:

• GER and FER have distinct epidemiological drivers but occur in overlapping environments.
• Effective ear rot management requires breeding for resistance to multiple pathogens, integrating epidemiology with plant breeding, and addressing environmental stressors.