Seed Coating with Mycorrhizal Fungal Spores and LEIFSONIA Bacteria: A Tool for Microbiological Fertilization and a Seed Protection Strategy From Insect Damage

We aimed to develop a coating process for maize and sorghum in order to simplify the application of microbial fertilizers and increase seed resistance against insects. The coating is a thin layer of Rhizophagus fasciculatus and Rhizophagus aggregatus spores and Leifsonia sp. applied on the surface of seeds using three Arabic gum solutions as glue materials. The germinating capacities of seeds and coated inoculants were followed up to 4 months of storage between 6 °C and 25 °C conditions. The remaining seed batches were mixed with 5 days aged insects (Sitophilus zeamais and Rhyzopertha dominica). Insect emergences were daily monitored and their damages on seeds were followed. Coating with a 10% gum solution had no negative effect for maize and sorghum seed germination. Moreover, seeds can be stored for up to 4 months at 6 °C without losing their germinability. Nevertheless, coating with 15 and 20% gum decreased the germinating characteristics of sorghum small seeds. Furthermore, incorporating fungal spores through seed coating did not alter mycorrhizal spores in generating root colonization. Lastly, the coatings decreased significantly the insect emergences with less seed attacks and seed weight losses although no gum dose is able to completely stop the emergence of S. zeamais and R. dominica.