Application of formulated rhizobacteria against root rot of field pea

Abstract

Formulations of bacterial biocontrol agents were evaluated for the control of pea root‐rot caused primarily by Pythium ultimum and Rhizoctonia solani, at different levels of disease severity in field trials. Pseudomonas fluorescens (strain PRA25) in a peat‐based formulation increased yield by 17% over the untreated, in a trial with light disease infection, and by 120% in another with moderate infection. Other bacteria including P. cepacia (strain AMMD) and fluorescent pseudomonads increased seedling emergence, and decreased disease incidence and severity, but with variable effects on yield when disease level was light to moderate. Biocontrol agents resulted in only limited control when disease was severe. Control with Captan did not differ significantly from that obtained with bacterial biocontrol agents. The application of Rhizobium granular inoculum together with PRA25 granules did not differ from other treatments in disease control, indicating that Rhizobium is compatible with biocontrol agents. The population dynamics of a fluorescent pseudomonad introduced into the rhizosphere in peat or granular formulation was monitored using an antibiotic‐resistant mutant marker strain. The bacterium in peat formulation established a considerably higher population than that in granular formulation in 1993 trials, and a slightly higher population in 1994 trials. The higher population may have been responsible for the efficiency of root colonization and the effectiveness of disease control.

Burkholderia ambifaria sp. nov., a novel member of the Burkholderia cepacia complex including biocontrol and cystic fibrosis-related isolates.

“…This strain was isolated from apparently healthy pea plants in Wisconsin (USA) in 1985. Several studies have shown that strain LMG 19182 is very effective in controlling phytopathogenic Pythium species (responsible for preand post-emergence damping-off in peas) (Parke, 1990 ;Parke et al, 1991 ;Xi et al, 1996) and Aphanomyces euteiches (responsible for root-rot and the main factor limiting pea production in the American Midwest) (King & Parke, 1993). In an ongoing survey of B. cepacia-like isolates by means of whole-cell protein analysis, amplified fragment length polymorphism (AFLP) fingerprinting and sequence analysis of the recA gene, 18 isolates from human clinical and environmental specimens exhibited similarity towards B. cepacia LMG 19182.…”

Isolation, selection, and characterization of beneficial rhizobacteria from pea, lentil, and chickpea grown in western Canada

“…Biofertilizers containing symbiotic N 2 -fixing R. leguminosarum and phosphate-solubilizing microorganisms, such as Nodulator1 (Becker Underwood Inc., Saskatoon, Saskatchewan) and Tag Team1 (Philom Bios Inc., Saskatoon, Saskatchewan), are recognized as beneficial inputs by Western Canadian pea and lentil growers. Xi et al (1996) reported that several fluorescent pseudomonads and Pseudomonas spp. strains PRA25 and AMMD were antagonistic to the pea root rot pathogens Pythium ultimum and Rhizoctonia solani in field trials in Saskatchewan.…”

Efficacy of Clonostachys rosea strain ACM941 and fungicide seed treatments for controlling the root rot complex of field pea

“…The microorganisms identified as potential bioagents include Bacillus subtilis (Ehrenberg) Cohn (Hwang and Chakravarty 1992), nonpathogenic Fusarium oxysporum (Oyarzun et al 1994), Gliocladium virens Miller, Giddens, and Foster [syn. Trichoderma virens (Miller et al) von Arx] (Hwang and Chakravarty 1993), Penicillium oxalicum Currie & Thom (Windels and Kommedahl 1978), Pseudomonas cepacia Palleroni & Holmes and P. fluorescens Migula (Parke et al 1991;Xi et al 1996), Trichoderma hamatum (Bon.) Bain.…”