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Influence of soil pH and liming on Fusarium crown rot of wheat

Kurtis Schroeder: University of Idaho

<div>Fusarium crown rot is a common disease of wheat worldwide. In the dryland wheat producing areas of northern Idaho and eastern Washington, Fusarium crown rot is caused by the soilborne pathogens <em>Fusarium culmorum </em>and<em> F. pseudograminearum.</em> Previous research suggests a possible correlation between decreasing soil pH and decreasing incidence of Fusarium crown rot. With the interest in soil liming to remediate low soil pH in the region, other potential outcomes of liming are being explored. A series of greenhouse and field studies was conducted to determine the influence of soil pH and liming on Fusarium crown rot. In inoculated greenhouse studies, a soil with a pH of 4 was adjusted to 5, 6 or 7 with calcium carbonate. The highest severity of Fusarium crown rot was observed at a pH of 6 with the lowest levels of disease at 4 and 7. In field trials, sensitive spring wheat varieties were seeded into a soil with a pH of 4.2 or limed with 11.2 metric tons calcium carbonate/ha (NuCal fluid lime) to achieve a pH of 6 in the top 15 cm of soil. In inoculated plots, there was a trend toward increased severity in the limed plots. While there was a positive yield response for the limed plots, Fusarium crown rot did not influence yield. These data suggest that as fields are limed, the severity of Fusarium crown rot may increase, although the impact is likely to be minimal.</div>