Waste conversion for organic fertilizer and fungal production to promote crop plants and control pests

A set of bottom-up interactions can be observed between soil, plant and pest. In rural areas, the discharge of livestock excrement is the main cause of water environmental pollution but with potential transformation into organic fertilizer using earthworms or black soldier flies. The use of such organic fertilizer alone or in combination with some fungi can affect pest growth and reproduction. The application of fungi also affected the growth and reproduction of pea aphid and fall armyworm. Firstly, dairy cattle farming produce large amounts of wastewater and it causes environmental pollution. Here, an improved vermicomposting system was applied to dairy farm wastewater with different combinations of organic substrates such as cow manure and rice straw in rural solid waste. Earthworm growth in vermicomposting were positively correlated with the C/N ratio, organic matter content and pH. Percentages of minerals increased in vermicomposting while organic matter content, C/N ratio, and cellulose declined as a function of the vermicomposting period. Final vermicompost was better for the absorption of plants. Continuous wastewater addition improved the effective transformation of organic waste to allow valorizing a broad range of organic residues, and avoid the risk of environmental pollution in dairy cattle farming. Secondly, multi-function fungi were used to promote plant growth. Inoculation with Phosphate-solubilizing microorganisms not only improved the growth of rape, but also increased phosphorus availability. We also obtained a novel gene from Penicillium oxalicum I1 whose overexpression in Escherichia coli increased the secretion of acetic acid helping to understand what was the function of the gene isolated from P. oxalicum as well as that of its homologs found in several other species of the Penicillium genus. Finally, fungi and compost were used to control pest included fall armyworm and pea aphid. Pest developmental durations were longer while reproductive ability was lower. Population dynamics of pests differed among the organic fertilizer treatments with vermi- or entomo-composts. Also, both entomopathogenic fungi and organic fertilizers effectively control aphids. Bioassays with Aspergillus flavus and A. niger allowed to control aphids To conclude, organic fertilizers and fungus synergistically reduced pest fertility and increased the death rate. To the best of our knowledge, this is the first report on the combined use of compost and multifunctional fungi to promote crop plants and synchronally control different pests such as aphid and moth.