Damping off

Damping off
    Causal organism: Pythium spp
     Symptoms
    • Pre emergent damping off.
    • Tubers or crowns fail to germinate. Rotting of tubers or crowns take place inside
    • the soil.
    • Post emergent damping off. Water soaking lesions on collar region, leading to rotting and damping off. .
    • Stem size reduction. Toppling over of seedlings & death.
    Taxonomy
    Kingdom: Chromista
     Division : Oomycota
    Class : Oomycetes
     Order : : Peronosporales
    Family : Pythiaceae
    Genius : Pythium.
    Etiology
    • Aseptate Mycelia, inter & intracellular haustoria.
    • Asexual spores: Zoospores and sporangia
    • Sexual Spores: Oospores.
    Epidemiology
    • Temperature:18-22?C.
    • RH: 90-95%
    • Susceptible host
    • Primary source of inoculums: Oospores and dormant mycelia in debris.
    • Secondary source of inoculums: Air born zoospores.
    Management
    • Use healthy tubers.
    • Follow raised bed method.
    • Reduce seedling density.
    • Application of biological agents.
    • Drench c.o.c 3g/l

Last modified: Thursday, 1 March 2012, 10:05 AM