Graber, E.R., Department of Soil Chemistry, Plant Nutrition and Microbiology, Institute of Soil, Water and Environmental Sciences, Agricultural Research Organization (ARO), Bet Dagan, Israel
Frenkel, O., Department of Plant Pathology and Weed Research, Institute of Plant Protection, Agricultural Research Organization (ARO), Bet Dagan, Israel
Jaiswal, A.K., Department of Soil Chemistry, Plant Nutrition and Microbiology, Institute of Soil, Water and Environmental Sciences, Agricultural Research Organization (ARO), Bet Dagan, Israel, Department of Plant Pathology and Weed Research, Institute of Plant Protection, Agricultural Research Organization (ARO), Bet Dagan, Israel, Department of Plant Pathology and Microbiology, Robert H. Smith Faculty of Agriculture, Food and Environment, Hebrew University of Jerusalem, P.O. Box 12, Rehovot, Israel
Elad, Y., Department of Plant Pathology and Weed Research, Institute of Plant Protection, Agricultural Research Organization (ARO), Bet Dagan, Israel

The purpose of this review is to examine how biochar additions to soil can affect plant diseases caused by soilborne pathogens, with particular attention to mechanisms and knowledge gaps. Until now, biochar soil amendment has been reported to affect the progress of diseases caused by soilborne plant pathogens in six distinct pathosystems. Disease severity frequently exhibits a U-shaped response curve, with a minimum at some intermediate biochar dose. Alteration of plant disease intensity by biochar added to soil may result from its varied influences on the soil-rhizosphere-pathogen-plant system. These influences may involve myriad biochar properties such as nutrient content, water holding capacity, redox activity, adsorption ability, pH and content of toxic or hormone-like compounds. The direct and indirect impacts of biochar on the soil environment, host plant, pathogen and the rhizosphere microbiome can have domino effects on both plant development and disease progress. © 2014 Taylor & Francis.