Spatial pattern analysis of root rot-root knot disease complex in an infested eggplant field

Abstract

The spatial pattern of Meloidogyne javanica in soil, root gall intensity, and colonization frequency of two soilborne fungi (Fusarium solam' and Rhizoctonia salam') on roots in an egg plant field, detected using various pattern detection indices, demonstrated non-randomness and patterns of aggregation. Morisita's index was computed for various quadrat (block) sizes to analyse the scale of pattern. Greatest heterogeneity was found at the smallest quadrat size and lowest at the larger sizes. Root gall intensity and nematode densities in soil were positively correlated at all block sizes. Colonizing frequency of the two fungi was positively correlated with galling intensity only at the smaller block sizes. The possible implications of spatial pattern of nematode populations with regard to sampling efficiency and interaction with plant pathogenic fungi are discussed.