Detection of Aphanomyces euteiches in Field Soil from Northern Idaho by a Wet-Sieving/Baiting Technique

Abstract

Aphanomyces euteiches was detected at three locations in northern Idaho by a wet-sieving technique. Five-day-old pea seedlings were used to bait the fungus from the sieved organic fraction from 10 soil samples per field. Inoculated seedlings in rolled germination paper were incubated and observed at weekly intervals for 3 wk. Almost all fields sampled in the Grangeville area were severely infested, and fields in the Kendrick area and two out of six fields in the Genesee area were heavily infested with A. euteiches. This wet-sieving technique gave results similar to the greenhouse-pot technique currently used to determine Aphanomyces root rot potential and required no greenhouse space or special watering requirements. This technique revealed that infective oospores of A. euteiches were as deep as 60 cm in the soil profile and were present in areas with poor drainage in fields with low inoculum levels overall. A hierarchical statistical analysis was used to separate differences in inoculum levels within areas and between fields. Common root rot of peas (Pisum sativum L.), caused by Aphanomyces euteiches Drechs., is a very destructive Cooperative investigations of the ARS, USDA, and the

Quantitative trait loci for partial resistance to Aphanomyces root rot in pea

“…Several cultural and prophylactic methods of disease management are recommended to prevent losses and include: (1) avoidance of pea crops in moderately to highly infested fields; prediction tests have been developed to identify the pathogen in infested soils and assess the root rot potential of soils (Kraft et al 1990; Williams-Woodward et al 1998;Vandemark et al 2000);…”

Spatial distribution of Aphanomyces euteiches inoculum in a naturally infested pea field

“…According to Burke et al (1970), this organism predominates in the layer of ploughed soil. However, Kraft et al (1990) found it up to 60 cm down in the soil profile. Consequently, the main objective of this study was to investigate the precise horizontal and vertical distribution of Aphanomyces root rot, based on disease severity (DS) data.…”

Soilborne Diseases and their Control

“…There are no economically feasible control practices for Aphanomyces root rot other than to avoid planting a susceptible legume in heavily infested fields (Kraft et al, 1990). Long-term rotations with crops that delay or reduce inoculum build-up, coupled with field indexing to determine field root rot potential, is the only means of control (Hagedorn, 1984;Kraft et aI., 1990).…”