VIEW ARTICLE

Ecology and Epidemiology

Sporulation and Survival of Conidia of Cephalosporium gramineum as Influenced by Soil pH, Soil Matric Potential, and Soil Fumigation. L. P. Specht, Postdoctoral research associate, Department of Plant Pathology, Washington State University, Pullman 99164-6430; T. D. Murray, Assistant professor, Department of Plant Pathology, Washington State University, Pullman 99164-6430. Phytopathology 79:787-793. Accepted for publication 22 February 1989. Copyright 1989 The American Phytopathological Society. DOI: 10.1094/Phyto-79-787.

In growth-chamber studies conducted at 5 and 15 C, sporulation of Cephalosporium gramineum on artificially colonized oat kernels on soil and survival of conidia in soil were significantly greater at soil pH 4.7 than at 5.7–7.5. Conidial survival also was greater at pH 7.5 than at 5.7–6.7, which produced a significant curvilinear relationship between soil pH and conidial survival. Sporulation of C. gramineum on oat kernels increased, whereas conidial survival decreased, as soil matric potential increased from –0.06 to –0.01 MPa. Survival of conidia always was high in soil at –0.06 MPa regardless of soil pH, but was low and influenced by pH at matric potentials of –0.03 and –0.01 MPa. Pretreatment of moderately acid (pH 5.5) soil with chloropicrin (0.2 ml/kg of moist soil) resulted in large reductions in total population densities of fungi and actinomycetes (but not bacteria) and in a significant increase in conidial survival.