Submitted to: American Phytopathological Society Annual Meeting
Publication Type: Abstract Only
Publication Acceptance Date: 2/17/2011
Publication Date: 6/17/2011
Citation: Canaday, C.C., Donald, P.A., Mengistu, A. 2011. Increases in snap bean and soybean seedling diseases associated with a chloride salt and changes in the micro-partitioning of tap root calcium. American Phytopathological Society Annual Meeting. 101:S26. Interpretive Summary:
Technical Abstract: In a series of field experiments from 1995 through 2010, the incidence of seedling diseases of snap bean and soybean caused by Rhizoctonia solani, Macrophomina phaseolina, Pythium spp., and Fusarium spp. was greater with an application of KCl than with K2SO4 applied at 93 kg K/ha. To determine if the observed increases could be due to a change in root calcium associated with chloride salts, soybeans were grown in pasteurized silt loam field soil and treated with KCl, K2SO4, MgCl2, and NaCl at 400 ppm Cl or 441 ppm K. After 10-12 days, portions of lateral and tap roots were subjected to elemental analysis using a Philips LX30 ESEM equipped with an energy dispersive x-ray analyzer. Calcium levels in the outer cell layers of tap roots, but no lateral roots, treated with KCl and MgCl2 were lower than the untreated control. There was also a notable decrease in calcium levels with NaCl. Compared to the untreated control, there was no change in root calcium with K2SO4. The chloride salt, KCl, may have predisposed the seedling roots to pathogen infection in the field studies by reducing the amount of calcium available for plant defense mechanisms.