Graphical abstract

Sesame ( Sesamum indicum L.), the “Queen of oil seeds” is being infected with pathogens, i.e. , fungi, bacteria, virus and nematodes. Fusarium oxysporum sp. sesami (Zap.), is one of the fiercest pathogens causing severe economic losses on sesame. This work aimed to evaluate the impact of the cultivation of some preceding crops and seed inoculation with antagonistic predominant rhizospheric bacteria and actinomycetes on the incidence and development of Fusarium damping-off and wilt disease. Results showed that the lowest pre and/or post-emergence damping-off and wilt of sesame were recorded after onion and garlic, followed by wheat compared to clover in both the 2019 and 2020 seasons. In vitro , soil extracts from plots where onion and garlic have been cultivated slightly decreased the conidia germination and mycelium radial growth of F. oxysporum . The numbers of sesame rhizospheric F. oxysporum and fungi were lower after the cultivation of onion and garlic than those after wheat and clover. However, the numbers of actinomycetes and bacteria were higher in the onion, garlic, and clover rhizosphere than wheat. Among all isolated bacteria and actinomycetes associated with sesame roots cultivated after preceding plants, the Tricoderma viride and Bacillus subtilis (isolate No.3) profoundly reduce F. oxysporum mycelial growth in vitro . When sesame seeds were inoculated with Tricoderma viride, Bacillus subtilis, Streptomyces rochei and Pseudomonas fluorescens, the disease incidence of damping-off and wilt significantly decreased in the greenhouse and field trials conducted in both tested growing seasons, also had highly significant on plant health and growth parameters. Therefore, the current study suggested that using the preceding onion and garlic plants could be used for eco-friendly reduction of damping-off and wilt disease of sesame.

No abstract

This study was carried out during two successive seasons 2014 and 2015 for evaluating the effect of inoculation with Bradyrhizobium sp, Bacillus megaterium, Bacillus circulans, Glomus macrocarpum instead a part of chemical fertilization in the presence of biocontrol agent i.e., Pseudomonas fluorescens on some microbial enzymes activity, growth characteristics, some biological constituent as well as yield and its components for optimal nutrition and some attributes of cowpeas. Obtained data showed significant increases of dehydrogenase (DH), nitrogenase and phosphatase activity in both seasons using of the combination of biofertilization and chemical nitrogen fertilization. Moreover, the values of NH4-N, NO3-N, available-P and soluble-K were the highest records with dual application of biofertilizers and half dose of chemical fertilization. Concerning, vegetative growth parameters and total yield, NPK-microbial inoculants combined with NPK-mineral fertilizers had the highest values. The results of this study suggest that, it may be replaced the mineral fertilizers by biofertilizers, even partially, to produce a better food and such integrated nutrient management program should be followed to produce the highest yield of cowpea.

This study was executed during two successive seasons 2014 and 2015 for evaluating the effect of inoculation with Bradyrhizobium sp, Bacillus megaterium, Bacillus circulans, Glomus macrocarpum and Pseudomonas fluorescens on infection percentage, enzymatic activity, growth characteristics, total phenol, peroxidase and polyphenol oxidase activity in presence or absence of Fusarium oxysporum in sterilized or non-sterilized soil under greenhouse condition. The obtained results observed that the tested strains showed suppression for F. oxysporum in vitro. Similar results were obtained under greenhouse experiment where the inoculation of soil with biofertilizers strains in presence of P. fluorescens showed the lowest records of infection percentage as well as the higher values of enzymatic activity, growth characteristics, total phenol, peroxidase and polyphenol oxidase activity compared to full dose of chemical fertilizers treatment. This study provides evidence for diminishing the adverse evolved from the continues application of chemical fertilizers in high doses and replacing it (at least partially) through biofertilizers and biocontrol application.