A comprehensive review on biochar against plant pathogens: Current state-of-the-art and future research perspectives

Plant pathogens cause a serious menace to food production. The diseases caused by pathogens are estimated to cause a yield loss of about 14.1 %, whereas, in India, up to 26 %. Several plant pathogens like Pythium, Phytophthora, Rhizoctonia, Sclerotinia, Fusarium, and Verticillium can cause 50-75 % yield losses in cereals, cotton, and horticultural crops (fruits, vegetables, and flowers) 10-100 % in pulses, 30-60 % loses in oilseed crops and 40-50 % in plantation crops. Biochar as soil amendment is emerging as an effective environment friendly substitute for fungicides to counter plant pathogens. It has also been reported to induce resistance in plants to combat plant pathogens by activating the two important defense pathways such as salicylic acid, jasmonate/ethylene defense, and triggering the plant's antioxidant enzymatic activities. Biochar promotes soil health and consequently improves the plant health, resulting in reduced incidence of disease. This novel amendment also helps in the priming of expression of genes against foliar fungal pathogen infection. This review paper will summarize the effect of biochar incorporation in the plant disease management as well as on their growth parameters.