VIEW ARTICLE

Regression of Tobacco Black-Shank Index on Soil Calcium. Randall R. Kincaid, Professor of Plant Pathology, now deceased, University of Florida, Institute of Food and Agricultural Sciences, Agricultural Research and Education Center, Quincy 32351; Frank G. Martin(2), and Fred M. Rhoads(3). (2)Associate Professor, (Associate Statistician), University of Florida, IFAS, Statistics Department, Gainesville 32601; and (3)Assistant Professor, (Assistant Soil Chemist), University of Florida, Institute of Food and Agricultural Sciences, Agricultural Research and Education Center, Quincy 32351. Phytopathology 62:302. DOI: 10.1094/Phyto-62-302.

The development of tobacco black shank (Phytophthora parasitica var. nicotianae) in unfumigated soils was directly related to soil calcium expressed as per cent of soil cation-exchange capacity (CEC). Development of the disease in fumigated soils was quadratically related to soil calcium, with maximum disease occurring at a relatively high Ca level of 67% of CEC. Where black shank is an important factor in tobacco production, applications of liming materials should be kept to a minimum consistent with good yield and quality of the crop.