Elad, Y., Department of Plant Pathology and Weed Research, Volcani Center, Agricultural Research Organization, United States
David, D.R., Department of Plant Pathology and Weed Research, Volcani Center, Agricultural Research Organization, United States
Harel, Y.M., Department of Plant Pathology and Weed Research, Volcani Center, Agricultural Research Organization, United States
Borenshtein, M., Department of Plant Pathology and Weed Research, Volcani Center, Agricultural Research Organization, United States
Kalifa, H.B., Department of Plant Pathology and Weed Research, Volcani Center, Agricultural Research Organization, United States
Silber, A., Department of Soil Chemistry, Volcani Center, Agricultural Research Organization, Bet Dagan 50250, Israel
Graber, E.R., Department of Soil Chemistry, Volcani Center, Agricultural Research Organization, Bet Dagan 50250, Israel

Biochar is the solid coproduct of biomass pyrolysis, a technique used for carbon-negative production of second-generation biofuels. The biochar can be applied as a soil amendment, where it permanently sequesters carbon from the atmosphere as well as improves soil tilth, nutrient retention, and crop productivity. In addition to its other benefits in soil, we found that soil-applied biochar induces systemic resistance to the foliar fungal pathogens Botrytis cinerea (gray mold) and Leveillula taurica (powdery mildew) on pepper and tomato and to the broad mite pest (Polyphagotarsonemus latus Banks) on pepper. Levels of 1 to 5% biochar in a soil and a coconut fiber-tuff potting medium were found to be significantly effective at suppressing both diseases in leaves of different ages. In long-term tests (105 days), pepper powdery mildew was significantly less severe in the biochar-treated plants than in the plants from the unamended controls although, during the final 25 days, the rate of disease development in the treatments and controls was similar. Possible biochar-related elicitors of systemic induced resistance are discussed. © 2010 The American Phytopathological Society.