Molecular Test and Reduction of Stalk and Kernels Rots Disease through Controlling of Leaf Blight and Stem Borers in Maize

Abstract

During two growing seasons, a field experiment was performed and conducted to observe the reaction cultivars of SC10, TWC320 and Balady to maize leaf blight disease under artificial infection with the causal agent Exserohilum turcicum. The efficacy of leaf blight disease and corn borer insect management as importance tools to control of stalk rot complex, and ear & kernels rot diseases of maize
was also investigated. The obtained data had the same trend. The reaction of the tested maize cultivars to leaf blight disease indicated that, the single cross 10 was ranged from highly resistance HR and resistance R. The three way cross 320 ranged from R to moderately resistant MR, while, the Balady cultivar ranged from MR to MS. Data of stalk rot complex showed that, the lowest infection percent
was recorded in plots which sprayed against both of leaf blight disease (Dithane M45) and corn borer (Lannate 90% SP). The highest infection percent by stalk rot complex recorded in the control plots (which not sprayed by any ones). The fungus Fusarium verticilioides was the prevalent causing stalk rot complex, during the two seasons with all the tested maize cultivars and all tested treatments. It was
significantly followed by Magnaporthiopsis maydis. The molecular identification reveal that the collected isolates were recognized as F. verticilioides and M. maydis based on ITS sequences analysis. Other fungi i.e., Macrophomina phaseolina, Alternaria spp., Penicillium spp. and Aspergillus spp. had the lowest infection percentage of stalk rot disease. Data indicated that, positive correlation was found
between infection by corn borers % and plants lodging %, in all maize cultivars. Also, the spraying against corn borer and leaf blight disease lead to the lowest infection by stalk rot disease and highest value of weight of 100 kernels as well as the highest of yield production comparing with control treatment. The fungus F. verticilioides also caused the highest infection percentage of ear and kernel rot disease with all the tested maize cultivars and under all tested treatments. While, other fungi i.e, Aspergillus niger, A. flavus and Penicillium spp. recorded the lowest infection percentage of ear and kernel rot disease. In generally, the lowest infection percent by ear and kernel rot disease was recorded  in plots which sprayed against leaf blight and corn borer. Therefore, this study concluded that, the control both of northern leaf blight disease and insects’ infection during growing season resulted in finally the lowest infection by stalk rot complex and kernels rot diseases in maize.