Invasive Species Compendium

Detailed coverage of invasive species threatening livelihoods and the environment worldwide

Abstract

Distribution and abundance of Aphanomyces euteiches in agricultural soils: effect of land use type, soil properties, and crop management practices.

Abstract

Aphanomyces euteiches is a soil-borne pathogen that causes root rot in susceptible pulse crops. Although widespread across Canada, A. euteiches was not reported in Saskatchewan until 2012. The distribution of this pathogen across the Canadian prairies is unknown and it is unclear whether it is native to the region. The objective of this study was to conduct a survey of A. euteiches across the major agricultural soils of Saskatchewan, Canada to determine its distribution and to assess the relative importance of factors related to its distribution and possible spread across the province. Soil samples were collected from lentil and pea fields and their associated roadside ditches, as well as from native and tame rangelands. Soil samples were analyzed using a quantitative polymerase chain reaction (qPCR) assay to detect and quantify the presence of A. euteiches. In addition, root rot severity was assessed on affected pea and lentil plants, and the physical and chemical properties of the soils were measured. A. euteiches was present across all land use (i.e., annual cropland, roadside ditches, and rangeland) and soil types in Saskatchewan. A. euteiches abundance was highest in samples collected from annually cropped fields. Within annual cropland, A. euteiches abundance was higher in pea fields than lentil fields. Soil moisture, total and organic carbon, and total nitrogen were positively correlated to A. euteiches abundance in field and roadside soils. Based on this survey, A. euteiches is wide-spread across all the major agricultural regions of Saskatchewan and is not limited to specific soil or land use types. The frequent detection of A. euteiches in native rangeland indicates it is likely native to Saskatchewan. The significant relationship between A. euteiches gene abundance and disease severity in pea fields indicates that the qPCR assay may be a useful indicator for predicting the potential for certain agricultural soils to cause A. euteiches root rot in pea crops.