Insect ear‐feeding impacts Gibberella ear rot and deoxynivalenol accumulation in corn grain

• Published in: Crop, forage & turfgrass management forage & turfgrass management, 2024-06, Vol.10 (1), p.n/a
• Main Authors: Singh, Maninder P., DiFonzo, Christina D., Fusilier, Katlin M., Kaur, Harkirat, Chilvers, Martin I.
• Format: Article
• Language: English
• Subjects: corn; deoxynivalenol; ear rot; forage; fungal growth; fungi; fungicide application; Fusarium; grain quality; insects; Michigan; pathogens; turf management; Zea mays
• ISSN: 2374-3832; 2374-3832
• DOI: 10.1002/cft2.20258

High deoxynivalenol (DON) levels in corn (Zea mays L.) is a grain quality issue for many growers in the US Great Lakes region. High DON levels can be attributed to the interaction of environment, pathogen (Fusarium spp. causing ear rot), and hybrid susceptibility. However, ear‐feeding insects can provide easy access for fungal infection and increase DON accumulation, hence the evaluation of insect protection strategies such as hybrid insecticidal proteins is crucial. Field trials were conducted at four locations in Michigan to study the impact of hybrids insect protection trait on ear injury, ear rot infection, and DON levels. Fungicide application (prothioconazole at silking stage) was conducted at two locations and included non‐treated control. Insect feeding incidence (IFI) and ear rot incidence (ERI) were correlated at three locations but were stronger at locations with environments not conducive to fungal growth soon after silking. Correlation between IFI and DON was observed only at locations with highest insect pressure. Hybrid with Vip3A protein reduced IFI by >70% at all locations but lowered DON concentration at one out of three tested locations compared to non‐Vip3A hybrids. Fungicide application reduced ear rot severity at one of two locations but did not impact ERI or DON levels. Overall, results showed that ear‐feeding by insects can lead to an increase in ear rot and DON levels, and use of hybrids with Vip3A protein can reduce DON levels especially under high insect pressure. Core Ideas Ear‐feeding by insects can lead to ear rot infection and deoxynivalenol (DON) accumulation in corn grain. Use of effective insect protection trait in hybrid selection reduced ear injury by >70% and can lower DON levels. Fungicide application reduced ear rot at one location but did not impact DON levels at both study locations. Optimal DON management strategies might vary based on field‐specific environmental conditions.