Soil and Foliar Applications of Calcium Chloride and Calcium Nitrate to Control Tipburn of Head Lettuce. I. J. Misaghi, Department of Plant Pathology, University of Arizona, Tucson 85721. R. G. Grogan, Department of Plant Pathology, University of California, Davis 95616. Plant Dis. 65:821-822. Accepted for publication 16 January 1981. Copyright 1981 American Phytopathological Society. DOI: 10.1094/PD-65-821.

Different amounts of calcium chloride and calcium nitrate were applied to the soil or to plants in field plots throughout Arizona and California during 1976 and 1980. Plants were rated for incidence and severity of tipburn in the field and in the laboratory. Tissue samples from plants in control and treated plots were also analyzed for calcium content. In only one of six trials, soil applications of calcium chloride at 224 or 448 kg/ha resulted in significant increases in tissue calcium and significant decreases in tipburn incidence and severity. In all field trials, however, soil and foliar applications of calcium nitrate and foliar application of calcium chloride at different levels did not significantly change tissue calcium and severity of tipburn.