Maize (Zea mays L.) is a staple food for the majority of the world's population. Fusarium verticillioides (Sacc.) Nirenberg (Teleomorph: Gibberella moniliformis Wineland; synonym: F. moniliformis) is both a saprophyte and a parasite of maize and can also be found as an endophyte. The presence of this fungus in maize constitutes an imminent risk due to its ability to produce fumonisins, mycotoxins with proven carcinogenic effects. The present work investigated biocontrol activity of Bacillus amyloliquefaciens and Microbacterium oleovorans against F. verticillioides infection and fumonisin B1 production in field-grown maize during four consecutive growing seasons. Treatment with B. amyloliquefaciens consistently reduced F. verticillioides inoculum and fumonisin content of harvested grains. F. verticillioides count and fumonisin levels correlated negatively with rainfall regimes; however, none of these parameters showed significant correlation with yields. Treatment with these biocontrol agents may improve phytosanitary quality of the grains and reduce toxicological risk in the maize agroecosystem. 1. Introduction Maize (Zea mays L.) is a staple food for the majority of the world’s population together with wheat and rice . The maize crop is currently the third most traded cereal with a total production of 817 million tones in over 159 million hectares by 2009 . About 35 to 40% of maize annual production of Argentina is obtained in Córdoba province . Maize is mainly used as a food source but it has become the most important raw material for animal feed and for several industrial processes [4, 5]. An increasing area is now being used to cultivate this crop, not only in temperate agro-ecological zones but also in all sorts of edaphic, altitudinal, and fertility conditions; which explains its global adaptability and its many types of varieties . In spite of this versatility, maize, as well as the rest of the agronomic crops, is not exempt of suffering from different diseases affecting its emergence, growth, development, and yield. Plant diseases cause global losses ranging between 9 and 22% of annual production, depending mainly on the crop and technological development of the country where the crop is . Fusarium verticillioides (Sacc.) Nirenberg (Teleomorph: Gibberella moniliformis Wineland; synonym: F. moniliformis) is both a saprophyte and a parasite of maize; it can be found as a systemic endophyte in a symptomless biotrophic state or as a hemibiotrophic pathogen depending on environmental conditions [8, 9]. Regardless the occurrence of
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