Soil borne pathogen and their impact

Soil borne pathogen and their impact

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  Dhiman Adhikary Id Number:17 P. Path JJ-02M
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  Presentation Topic Soil BornePathogens and Their Impact on Crop Production
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  Soil Borne Pathogen •Soil borne pathogens are tiny organisms like bacteria, viruses or fungi that infect plant roots, stems, and leaves • Reduced plant growth, increased costs to the growers, and potential damage to the environment • After all it lost the yield production • Soil is a reservoir of inoculums of these pathogens, the majority of which are widely distributed in agricultural soils
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  Soil Borne Disease: •The diseases that are caused by these pathogens which survive in the soil and in residues on the soil surface are defined as soil borne diseases. • Cause many destructive crop diseases such as # Damping-off, # Root rots, # Collar rots, # Stem rot and # Wilt diseases • Reduced plant growth, increased costs or significant economic loss to the growers and potential damage to the environment.
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  Survival of theSoil Borne Pathogen • Soil inhabitants (survive in soil for relatively longer periods), soil invaders (survive in the soil for relatively shorter periods). • Non-pathogenic and generally in the form of saprobes (organisms that live on decaying organic matter). • In crop debrisIn crop debris • In seedIn seed • On alternate hosts (including weeds)On alternate hosts (including weeds)
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  Types of Soil-bornePathogens • Fungus Root rots Stem, collar, and crown rots Wilt diseases, Damping off Diseases • Bacteria Erwinia (soft rot), Rhizomonas (corky root of lettuce) Streptomyces (potato scab, soft rot of Sweet potatos) • Viruses stunting and yellowing and spotting of lower leaves • Nematodes Root rot nematodes
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  Fungus diseases Root rots •Rootsystem to begin to decay •Include wilting, yellowing, stunting, dieback and eventual death •Pathogens infect the plant's roots and block the uptake and flow of water and nutrients through the plant. Cylindrocladium, Pythium, Phytophthora, and Rhizoctonia.
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  Stem, collar, andcrown rots • Affect the plant at ground level • Symptoms are similar to root rots, but since the rotting start above the soil line, it can be easier to detect early. Phytophthora, Rhizoctonia, Sclerotinia, and Sclerotium.
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  Wilt diseases: • wilting,chlorosis, necrosis, •premature leaf drop, •browning of the vascular system, stunting •cause wilting of the plants, despite adequate water. Fusarium oxysporum and Verticillium spp. Damping off disease •affect young seedlings. •infect the plants at germination or shortly after, causing sudden death Pythium, Phytophthora, Rhizoctonia and Sclerotium rolfsii.
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  Erwinia (soft rot) •wateryand soft decay of the tissue •change in color and in the case of a carrot •stem also rots and becomes mushy with its colorless Root rot nematodes •Stunted growth, •yellowing leaves, thinning plants, •damage in patches and premature wilting
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  Impact of soilborne pathogen on crop Soil borne pathogen is very harmful for the crop production. Most of the soil borne pathogen destroy the crop production. •Reduce the yield •Economic loss •Severe stage plant can’t survive Some soil borne pathogen is also beneficial for the crop production. •Some nitrogen fixing bacteria like Azotobactor, Rhizobium live in the plant root and produce nodule and fixation nitrogen from the air. This nitrogen is beneficial for the crop.
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  Management of Soilborne Pathogen • Growers must first know what pathogens are present, • Where they are prevalent, and • Finally how much inoculums is in the soil Soil borne pathogen can be manage by three ways • Cultural Control • Biological Control • Chemical Control
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  Cultural Control Fertilizer application: •Ammoniumbicarbonate reduce the viability of sclerotial bodies of S. rolfsii •Pythium and Phytophthora by application of phosphoric acid •Rypsum reduces the incidence of Macrophominain groundnut Providing good soil drainage and good air circulation among plants •Good soil drainage reduces the number and activity of certain oomycetes pathogens (eg.,Pythium) and nematodes. •Flooding fields for long periods or dry fallowing may also reduce Fusarium, Sclerotiniasclerotiorum, and nematodes
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  Crop Rotation Rotation withlegume and non-legume Tillage practices Deep ploughing of crop residues Soil amendments •organic amendments like saw dust, straw, oil cake, etc •manage the diseases Pythium, Phytophthora, Macrophomina Soil Solarization •clear polyethylene is placed over moist soil during sunny summer days •increased soil temperature from solar heat
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  Biological control • Biologicalcontrol agents colonize the rizosphere, the site requiring protection • Flurescent psedudomonads are the most frequently used bacteria for biological control and plant growth promotion but Bacillus and Streptomyces species have also been commonly used.
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  Chemical Control • Fumigation,soil drenching and seed treatment • Fungicides like prothiocarb, propamocarb and metalaxyl are useful to control the soilborne pathogens • Fungicides used for soil treatments include metalaxyl, diazoben, pentachloronitrobenzene(PCNB), captan, and chloroneb
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  Thanks to All