Spatial Pattern of Southern Stem Rot Caused bySclerotium rolfsiiin Six North Carolina Peanut Fields

Abstract

Frequency distributions of southern stem rot lesions in 5 of 6 data sets from North Carolina peanut fields sampled in 1980-1982 were fitted (P = 0.13 to 0.75) by a negative binomial distribution, which indicated that disease occurred in a clustered pattern. Disease incidence ranged 5.4-32.3% in the 6 fields sampled. Estimates of the parameter k of the negative binomial distribution ranged 0.87-6.49 and generally increased with plot size and with the population mean. Incidence of southern stem rot lesions in 3 fields was positively correlated with soil bulk density (r = 0.47**). Spatial correlations calculated from data from 3 fields indicated different patterns of disease in each field.