Damaged corn ears

Integrated Mycotoxin Management in Corn Grain Through Control of Ear Rot and Western Bean Cutworm


Katlin Blaine, <msingh@msu.edu>, <chilvers@msu.edu> and <difonzo@msu.edu>

High deoxynivalenol (DON) levels in maize (Zea mays L.), caused by the interaction between hybrid susceptibility to ear rot (caused by Gibberella zeae), ideal weather conditions, and western bean cutworm (WBC) damage, can result in price dockage and other quality concerns. Host plant resistance and fungicide application can be used to minimize DON and other mycotoxin causing ear rots, however research is lacking on these strategies under varying environmental conditions. In this study, corn hybrids with varying levels of resistance to ear rot and different combinations of Bt proteins along with a targeted fungicide application of prothioconazole at silking were used to evaluate DON concentrations, ear rot levels, WBC damage, and maize yield at nine locations in Michigan. Across all data, a positive correlation (R2=0.78, p<0.001) was observed between WBC incidence and ear rot incidence. Moreover, ear rot index (incidence x severity) showed a positive correlation (R2=0.53, p<0.001) with DON concentrations. Hybrid selection impacted WBC incidence and severity (p<0.001 and 0.04, respectively), however no significant differences were observed between hybrids differing only in their Bt (Cry1F) traits. Hybrid susceptibility to ear rot was found to have an impact on ear rot incidence (p<0.001) but not on severity. Fungicide application did not reduce ear rot incidence (p=0.28) or severity (p=0.54). However, reduction in DON (p=0.04) was observed with fungicide application, possibly due to secondary fungal infections in the ear not being controlled by the fungicide. Grain yield also increased (p=0.006) with fungicide application, likely due to control of foliar diseases. Results indicated that hybrid selection and fungicide application did not minimize ear rot consistently across Michigan under 2017 environmental conditions but resulted in low DON levels in some instances. Overall, an integrated pest management approach must to be followed to minimize ear rot and associated mycotoxins in maize grain.



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