Fungi Resident in Chickpea Debris and their Suppression of Growth and Reproduction ofDidymella rabieiunder Laboratory Conditions

Abstract

AbstractFungi colonizing senescent chickpea (Cicer arietinum) stems and postharvest debris from Pullman, WA, were enumerated and identified with the objective of finding species potentially useful for biological control ofDidymella rabiei(conidial state = Ascochyta rabiei), causal agent of Ascochyta blight. In addition toD. rabiei, primary colonizers were, in order of decreasing abundance,Alternaria tenuissima,Al. infectoria,Ulocladium consortiale,Epicoccum purpurascens,U. atrumandFusarium pseudograminearum. Present at lower frequencies wereAl. malorum,Cladosporium herbarum,Aureobasidium pullulans,Clonostachys roseaand miscellaneous anamorphic ascomycetes. On agar media and autoclaved chickpea stems,Au. pullulansconsistently grew faster thanAs. rabiei, and excludedAs. rabieifrom the substrate. When stems received prior inoculation withAu. pullulansorCl. rosea, followed by inoculation with compatible mating types ofD. rabiei, formation of pseudothecia and pycnidia ofD. rabieiwas suppressed. Results suggest thatAu. pullulansandCl. roseacan inhibitAs. rabieiand its sexual stage,D. rabiei, on chickpea debris.Clonostachys roseaformed appressoria on, then invaded,hyphae ofD. rabiei. Small‐scale field experiments usingAu. pullulansandCl. roseahave been initiated.