Effects of elevated atmospheric CO2 concentration on the infection of rice blast and sheath blight

The effect of elevated atmospheric CO2 concentration oil rice blast and sheath blight disease severity was Studied in the Field in northern Japan for 3 years. With free-air CO2 enrichnient (FACE), rice plants were grown in ambient and elevated (approximate to 200 to 280 mu mol mol(-1) above ambient) CO2 concentrations, and were artificially inoculated with consist of Magnaporthe oryzae. Rice plants grown in an elevated CO2 concentration were more susceptible to leaf blast than those in ambient CO2 as, indicated by the increased number of leaf blast lesions. Plains grown Under elevated CO2 concentration had lower leaf silicon content, which may have contributed to the increased Susceptibility to leaf blast under elevated CO2 concentrations. In contrast to leaf blast, panicle blast severity wits unchanged by the CO2 enrichment under artificial inoculation, whereas it was slightly but significantly higher under elevated CO2 concentrations in a spontaneous rice blast epidemic. For naturally Occurring epidemics of the sheath blight development in rice plants, the percentage of diseased plants was higher under elevated as opposed to ambient CO2 concentrations. However, the average height of lesions above the soil Surface was similar between the treatments. One hypothesis is that the higher number of filters observed under elevated CO2 concentrations may have increased the Chance for fungal sclerotia to adhere to the leaf sheath at the water surface. Consequently, the potential risks for infection of leaf blast Would increase in rice grown under and epidemics of sheath blight elevated CO2 concentration.