F.verticilliodes (Sacc) Nirenberg (G) is the major pathogen of maize worldwide causing seedling, stalk and ear rots. Five isolates of F.verticilliodes have ability to infect maize Pioneer cultivar plants. The isolates varied in their infectivity, F.verticilliodes isolate 3 gave the highest stalk rot severity in both 2008 and 2009 growing seasons, followed by isolate 4, while isolate 5 was the lowest pathogenic one.
In vitro, the microelements [Zinc (Zn, manganese (Mn) and copper (Cu)] reduced linear growth of the pathogen. Manganese exhibited the highest toxic effect followed by zinc while copper exhibited the lowest toxic effect. The antagonistic effects of 3 P. fluresences isolates on mycelial growth on F.verticilliodes were in the range of 55.14 to 79.82%, P. fluresencesisolate (Pf2) considerably more antagonistic than other isolates. Under greenhouse conditions, treatment of maize plants with microelements decreased significantly disease severity. Manganese treatment was more effective than copper and zinc treatments. The bio control with P. fluresences isolate (Pf2) provided moderate level of protection when used alone, while combination of Pf2 with microelements treatment significantly improved the biocontrol activity and significantly reduced disease severity compared with microelements alone. Microelements content increased with P. fluresences treatment comparing with control treatment.