Influence of Bt and environmental factors on Fusarium ear rot in maize

Authors: BUTOTO, E - North Carolina State University; ALSDORF, A - North Carolina State University; REISIG, D - North Carolina State University; Holland, James

Submitted to: Crop Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 5/30/2025
Publication Date: 7/14/2025
Citation: Butoto, E., Alsdorf, A.M., Reisig, D.D., Holland, J.B. 2025. Influence of Bt and environmental factors on Fusarium ear rot in maize. Crop Science. 65, e70103. https://doi.org/10.1002/csc2.70103.
DOI: https://doi.org/10.1002/csc2.70103

Interpretive Summary: Fusarium verticillioides is a common fungus that affects maize, causing Fusarium ear rot (FER) and producing fumonisin (FUM), a toxic substance harmful to humans and animals. Factors like drought, humidity, and insects affect the severity of FER and FUM. This study looked at FER, FUM, and insect damage in maize from North Carolina farms and how genetically modified (Bt) maize compared to non-Bt maize. Bt hybrids had less FER and insect damage on average, but FUM levels were similar in both types, with Bt hybrids showing slightly lower FUM. In some cases, FUM levels exceeded safe limits for consumption, with a non-Bt hybrid reaching 27.8 ppm. The study found several environmental factors linked to FER, FUM, and insect damage, though their effects were not always as expected. The results show that the interactions between ear rot, mycotoxins, and insects in maize are complex, and more research is needed with a larger sample size to better understand these factors.

Technical Abstract: Fusarium verticillioides is one of the most commonly reported pathogenic fungi of maize. It is responsible for Fusarium ear rot (FER) and fumonisin (FUM), a mycotoxin associated with illness in humans and animals that consume contaminated grain. Multiple factors, including drought stress, humidity, and insects, influence the severity of FER and FUM. This study aimed to assess the occurrence of FER, FUM, and insect feeding in maize grown on commercial farms in North Carolina and the impact of transgenic traits on their severity. We also attempted to identify important environmental factors specific to maize growth stages that contribute to FER and FUM during the growing season. Five hybrids (two Bt and three non-Bt) were average, lower FER and insect feeding compared to non-Bt hybrids. Although differences in FUM contamination were not significant, Bt hybrids had a numerically lower FUM than non-Bt hybrids. In some counties and years, the FUM levels were higher than those recommended for products intended for human and animal consumption, with the highest level of 27.8 ppm in a non-Bt hybrid. We identified several environmental covariates related to FER, FUM, and insect feeding, but their relationships to the traits of interest often contradict expectations based on previous research. The results highlight the complexity of ear rots, mycotoxin, and insects and their interaction in maize. It also highlights a need for a larger sample size in multiple environments with adequate variation in FER, FUM, and insect feeding to tease apart factors influencing ear rots and mycotoxins.