Biofungicide saves plants from fungal attacks Soil pathogens can attack crop plants. Friendly fungi come to the rescue. Climate Change and Environment Food and Natural Resources © Al.geba, Shutterstock Many plants have a beneficial, if not essential, relationship with soil fungi. Nevertheless, this can become unbalanced. Then fungi become parasitic, killing plants by draining them of nutrients. Each year, such fungal infections wipe out more than 125 million tonnes of crops worldwide. Yet, chemical fungicides are trouble too. They kill beneficial soil fungi, bringing serious consequences for plants. Furthermore, chemical fungicides cause numerous environmental effects, including irritation to humans at the least, and perhaps others yet unknown. Agricultural and horticultural industries need a way of dealing with fungal infections in non-chemical ways. The EU-funded BIOAVENGER project started development of such an alternative. The project’s product of the same name is a biofungicide for soil treatment. “BioAvenger combats fungal infection in plants in a natural way,” says Nadine Brinkmann, project coordinator. “The product uses beneficial fungi to fight harmful fungi.” Restoring balance Trichoderma atrobrunneum is a clade or sub-group of beneficial soil fungi. In healthy soil, it grows on plant roots, increasing the plants’ ability to obtain water and nutrients from soil. When artificially introduced to plants via the BioAvenger soil treatment, Trichoderma outcompetes harmful fungi. First, Trichoderma establishes itself between the cell walls of the host plant’s roots. This forces the plant to make the signalling molecules that activate its defences which include substances harmful to fungi. Then, since the signalling molecules have already been synthesised, the plant can rapidly respond to any genuine attack. Trichoderma breaks down the cells walls of the attacking fungi, and feeds on its remains. It also fosters root growth, making the plant more resistant to drought. The BioAvenger product contains biochar, which is essentially charcoal, although made from organic waste rather than wood. It is produced via the same low-oxygen combustion process as charcoal. Double action Biochar and Trichoderma complement each other. The biochar’s large surface area increases the habitat available for Trichoderma and other microorganisms. Biochar also retains more than five times its own weight in water, which is available to the plants. Use of Trichoderma and biochar together greatly enhances the effect compared to either used singly. Biochar also improves soil fertility, fosters growth of beneficial fungi or bacteria, and removes chemical residues from the soil. The BioAvenger product can be used as either a cure or a preventative measure. If crop plants are sick, application of the treatment improves health within a month. Regular dosing over several months resulted in eradication of over 90 % of the invading fungi and up to 50 % more plant growth. The treatment also protects against infection. The product is not yet ready for commercial launch. “The upscaling is always challenging,” Brinkmann reports. “The fact that a product works at a small scale doesn’t necessarily mean it will work at a production level.” The team continues development and will soon be ready to apply for approval under EU regulations. When ready for commercial release, BioAvenger will offer an inexpensive, non-chemical treatment for agricultural fungal infections that improves plant productivity and soil health. The market and environmental benefits should prove substantial. Keywords BIOAVENGER, soil, Trichoderma, biochar, fungal infection, biofungicide, soil treatment
