Moko disease(wilt) of banana

Moko wilt of Banana

    Causal organism: Ralstonia solanacearum (Yubucchi et al.)
    It was first recorded in Guyana in 1840. In India, the disease was first reported from West Bengal. Susceptible varieties are the Robusta and Poovan from Tamilnadu.

    Symptoms

    • Yellowing of younger leaves is the primary symptom.
    • Yellowing progresses downward gradually leading to drooping and drying of leaves
    • Fruit bunch size gets reduced with immature and irregular ripening of fruits. Infected fruits show cracking with bacterial ooze
    • Vascular browning of the fruit along with light coloured vascular discolouration is common.

    Moko_wilt_of_Banana

    Etiology

    • Pathogen is gram negative, lophotrichus bacteria. (More than one polar flagellum), multiplication occurs by bacterial fission.
    • Mode of Survival and spread
    • Primary source of inoculum: The bacterium is soil/water borne and also spreads through infected suckers/rhizomes. It survives in susceptible host like banana and heliconia.
    • Secondary source of inoculum: Bacterial cells spread through irrigation water and also through suckers used for planting.

    Epidemiology
    Soil temp 28-320c, relative humidity 87-92%, PH slightly acidic to neutral, clay loam and sandy loam soil and susceptible variety.

    Life Cycle

    • The bacteria survive through infected rhizomes and also in soil for 6 months to 2 years.
    • The spread is through use of infected rhizomes, cutting machetes at the time of planting, and through insects which carry bacteria from oozing suckers and male flowers and bracts to healthy inflorescence and other parts of the plant.
    • Entry into the host is mainly through injuries such as those caused during various cultural operations and attack of insects and nematodes.
    • The bacteria multiply rapidly in the xylem. Auxin balance of the plant is disturbed.
    • IAA is synthesized by the bacterium and by the host and accumulates due to inhibition of the auxin degrading system.
    • Loss of virulence in the bacterium is generally accompanied

    Management
    • Use disease free planting material
    • Use resistant varieties like Robusta and Grand naine.
    • Infected plants should be collected and burnt.
    • Give proper drainage and avoid movement of water from infected to healthy plants
    • Drip irrigation method reduces the spread of bacteria.
    • Chemicals: Apply Copper Oxychloride @ 3gm per lit and Sreptocycline @ 0.5 gm per lit as a soil drench
    • Use bio- agent like Pseudomonas fluorescens.

Last modified: Tuesday, 17 January 2012, 11:21 AM