Maize is considered one of the most susceptible crops to mycotoxin-producing fungi throughout the world, mainly belonging to the Fusarium spp. and Aspergillus spp. Maize is mainly used as animal feeds in Italy, as well as for human consumption, being essential for all the protected designation of origin (DOP) products. Our study investigated the occurrence of regulated mycotoxins in 3769 maize grain samples collected from 88 storage centers by the National Monitoring Network over an 11-year period (2011–2021). Moreover, an in-depth survey over a 4-year period, characterized by extremely different meteorological conditions, was conducted to investigate the co-occurrence of regulated, masked, and emerging mycotoxins. The survey confirmed that Fusarium spp. was the most frequent fungi and fumonisins were the main mycotoxins that were constantly detected in the different years and areas. Moreover, the areas characterized by high fumonisin levels were also the most prone to contamination by emerging mycotoxins produced by the same Fusarium species of the Liseola section. On the other hand, as a result of climatic changes, maize grains have also been affected by the increased frequency of aflatoxin accumulation. Deoxynivalenol, zearalenone, and other emerging mycotoxins produced by the same Fusarium species as the Discolor section occurred more abundantly in some areas in Northern Italy and in years characterized by predisposing meteorological conditions.

Impact of sowing time, hybrid and environmental conditions on the contamination of maize by emerging mycotoxins and fungal metabolites

Corn grain production could be affected by several fungal pathogens responsible for the production of mycotoxins. The aims of this study were to determine the evolution of phenolic acids and total antioxidant activity (TAA) during kernel development and to evaluate their potential protective role in minimizing mycotoxin contamination in 6 corn genotypes (four open-pollinated varieties and two hybrids) characterized by a wide array of kernel traits. TAA, total free and cell wall-bound phenolic acids showed significant differences among corn genotypes at different stages of development, with the highest values found at the beginning of kernel development. Ferulic, p-coumaric and caffeic acids were the main cell wall-bound phenolic acids during kernel development, while chlorogenic acid was the main free phenolic acid. A significant negative correlation was observed between deoxynivalenol contamination at harvest maturity and free phenolic acids and TAA at the beginning of kernel development, while no significant correlation was observed with fumonisin contamination. In conclusion, free phenolic acids are evidently involved in the resistance mechanism towards deoxynivalenol contamination, while their role towards fumonisin contamination was not elucidated under field conditions, implying that components other than phenolic acids may be responsible for this latter type of resistance.

Fusarium spp. are key pathogens in maize seeds and seedlings. The aim of this study has been to evaluate the effects of applying fungicides to maize seeds to increase the survival of seedlings and to enhance the early vigor and grain yield of the plants. The protective effects of 2-way (fludioxonil, metalaxil-M) and four-way (fludioxonil, metalaxil-M, azoxystrobin, thiabendazole) fungicide seed treatments were compared with an F. verticillioides seed infected control in 11 field trials carried out in North Italy. A second study focused on the impact F. verticillioides and F. graminearum seed-borne infection on plant growth and on the possible advantages of applying the previously reported seed dressing. The seed dressing increased the plant density, vigor during the whole vegetative growth cycle for all the production situations, and grain yield. F. verticillioides led to a higher seedling mortality than F. graminearum, while both species reduced plant growth and delayed the flowering date. Seed-borne infection has an important impact on both the population and vigor of maize plants. The four-way fungicide enhanced both the defense of the seedlings and the vigor of F. verticillioides infected plants, which in turn resulted in a significant improvement in grain yield, compared to a conventional two-way fungicide.