Prospects for biocontrol of brown rot disease of potato in vitro and under greenhouse conditions

Abstract

This investigation is a trial to biocontrol of brown rot disease of potato by basidiomycetes, wheat straw and spent mushroom straw. Bird's nest Cyathus stercoreus is firstly recorded in Egypt. It was found growing on manured soil at New Damietta. It is identified and isolated from its fruit body. Eight basidiomycetes including C. stercoreus were tested to antagonize Ralstonia solanacearum (causal agent of brawn rot disease of potato) in vitro. All of these fungi inhibited the growth of R. solanacearum and the largest inhibition zones were recorded with Cyathus stercoreus Egyptian strain and Agaricus campester Egyptian strain. Extract from the Cyathus stercoreus mycelia was studied using Thin Layer Chromatography (TLC), Infrared (IR) spectroscopic analysis and Nuclear Magnetic Resonance (NMR). The study suggested that the polysaccharide of this fungus has the antibacterial activity. C. stercoreus was selected to green house study. Water extract filtrate of raw wheat straw (wers) and of spent mushroom straw (wess) of three Pleurotus sp. were tested to inhibit R. solanacearum growth by applying disc-filter paper method. RSE filtrate and all the other three filtrates inhibited R. solanacearum growth. Water extract of Pleurotus columbinus spent wheat straw (wess) had the largest inhibition zone, so, it was selected to further study. In greenhouse experiment, the previous selected factors were used to estimate their ability to biocontrol R. solanacearum. The reported results revealed that the mycelial suspension of C. stercoreus (Css) had the best effect in reduction of the disease, plant health and plant production. Consequently, this is the first report of using C. stercoreus in biological control of plant diseases. Using of spent straw and raw straw powders and their water extracts had good results in controlling the disease and plant productivity. © 2008 Asian Network for Scientific Information.