Control of Cylindrocladium Black Rot of Peanut with Cultural Practices That Modify Soil Temperature. Jill R. Sidebottom, Former Research Assistant, Department of Plant Pathology, North Carolina State University, Raleigh 27695-7616. Marvin K. Beute, Professor, Department of Plant Pathology, North Carolina State University, Raleigh 27695-7616. Plant Dis. 73:672-676. Accepted for publication 17 February 1989. Copyright 1989 The American Phytopathological Society. DOI: 10.1094/PD-73-0672.

Development of Cylindrocladium black rot (CBR), a root and pod rot disease of peanut caused by Cylindrocladium crotalariae, is slowed when soil temperatures exceed 25 C and stops if temperatures exceed 35 C. Cultural practices that modify soil temperature were evaluated in 1985 and 1986 for their effect on CBR development in susceptible (Florigiant) and moderately resistant (NC 18416) peanut genotypes. Cultural practices included delayed planting (the recommended planting date was compared with planting 2 and 4 wk later), two row preparations (bedded and flat rows), and two row orientations (north-south and east-west). In both years, CBR incidence was less for NC 18416 than for Florigiant. Disease incidence was least at the last planting date for both genotypes in both years. Maximum and minimum soil temperatures in the row at 10 cm deep were greater in the 3-wk period following the last planting date than in a similar period following the first planting date. The decrease in disease incidence at the last planting date did not result in an increase in yield because of the shortened growing season. Disease incidence was less in bedded rows in 1985 than in flat rows. In 1986, there was more disease present in all treatments, and disease incidence that year was not affected by row preparation. Yields, however, were greater in bedded rows. Row orientation did not affect CBR development or yield for either genotype or year.

Keyword(s): Arachis hypogaea.