Field control of Fusarium ear rot, Ostrinia nubilalis (Hübner) and fumonisins in maize kernels

BACKGROUND: A six year study was conducted to evaluate the possible support of pesticides in mitigating mycotoxin contamination in maize grown in northern Italy. Different pesticides to control Ostrinia nubilalis (ECB), Fusarium verticillioides and Aspergillus flavus were considered to check their efficacy and the best schedule to reduce fumonisin and aflatoxin contamination. RESULTS: Fumonisin B1 (FB1) contamination at harvest has been reduced by ECB control while the addition of ingredients targeted to F. verticillioides gave a limited advantage, mainly with low FB1 contamination; nevertheless, fusaria control is relevant in high risk conditions, when FB1 is likely to exceed the legal limit. The combination of fungal and pest control in a single spray at silk browning stage (BBCH 67) is the best way of application. These results are robust because obtained in a 6 year trial, with relevant differences in meteorological conditions, ECB and fungal presence and mycotoxins contamination. CONCLUSION: Insecticides have been shown to give advantages in their application, while the low FB1 contamination in the final years of the study did not lead to conclusive data on the advantage of adding a fungicide. Chemicals applied never modified A. flavus incidence nor aflatoxin contamination (only detected in trace amounts).