Effect of Media on Growth and Interactions Between a Range of Soil‐borne Glasshouse Pathogens and Antagonistic Fungi

Abstract

SUMMARYThe growth of and interactions between the glasshouse pathogens, Rhizoctonia solani Kiihn, Fusarium oxysporum Schlect., Pyrenochaeta lycopersici Schneider & Gerlach, Phomopsis sclerotioides van Kesteren, Sclerotinia sclerotiorum (Lib.) de Bary and Botrytis cinerea Pers. and the antagonistic fungi, Trichoderma harzianum Rifai, Trichoderma viride Pers., Coniothyrium minitans Campbell, Gliocladium roseum (Link.) Bain and Pythium oligandrum Dreschlgr were examined on tap water agar, soil extract agar and potato dextrose agar. The medium had a significant effect on the growth rates of the fungi as well as the production of, and response to, volatile and non-volatile antibiotic compounds and hyphal interactions. Responses to the media appeared to be related both to inherent properties of the fungi and to their natural ecological behaviour. The significance of in vitro assays in screening systems for biological control agents of soil-borne plant pathogens is discussed.

Ectomycorrhizal symbiosis affects functional diversity of rhizosphere fluorescent pseudomonads

“…In the present study, the antagonistic ability of the 60 bacterial isolates was assayed in vitro. In the context of screening biocontrol agents against soil-borne pathogens, the significance of the in vitro antagonism assays is often controversial because the efficiency of biocontrol agents depends not only on their antagonism ability but also on their rhizosphere competence (Whipps, 1987;Lugtenberg et al, 2001). Nevertheless, the in vitro antibiosis assays constitute an efficient way to analyse the antagonistic potential of a bacterial community (Whipps, 1987).…”

“…In the context of screening biocontrol agents against soil-borne pathogens, the significance of the in vitro antagonism assays is often controversial because the efficiency of biocontrol agents depends not only on their antagonism ability but also on their rhizosphere competence (Whipps, 1987;Lugtenberg et al, 2001). Nevertheless, the in vitro antibiosis assays constitute an efficient way to analyse the antagonistic potential of a bacterial community (Whipps, 1987). Interestingly, we demonstrated that the Douglas fir-L. bicolor mycorrhizas and ectomycorrhizosphere selected P. fluorescens isolates that had a broader spectrum of antagonistic ability than the bulk soil isolates.…”

Inhibition de <i>Phytophthora palmivora</i>, agent de pourriture brune des cabosses de cacaoyer en Côte d’Ivoire, par <i>Trichoderma</i> sp.

“…La réaction à l'inoculation simultanée de Trichoderma et P. palmivora est estimée sur la fréquence et la taille des lésions formées sur la face latérale de la cabosse. L'évaluation d'inhibition de lésions sur cabosses exercée par un isolat de Trichoderma est estimée par le calcul du taux d'inhibition selon la formule décrite par Whipps (1997) : I (%) = (1-Cn/Co) x 100. Où I (%) représente inhibition moyenne en pourcentage, Cn est la note moyenne sensibilité à P. palmivora des cabosses en présence de Trichoderma et Co est la note moyenne sensibilité à P. palmivora des cabosses en absence de Trichoderma (témoin).…”

Assessment of the Antifungal Activity of Non-pathogenic Potatoassociated Fungi toward Fusarium Species Causing Tuber Dry Rot Disease

“…The percentage of growth inhibition (GI) rate of the pathogens was calculated using the following Whipps' [30] Morphological alterations of pathogen mycelium, removed from the confrontation zone, were observed under light microscope and described as compared to the untreated control at the end of the experiment.…”