Powdery mildew of Mango

Powdery mildew of Mango

    Powdery mildew is one of the devastating foliar diseases of mango affecting almost all the cultivars. In India, the disease is wide spread including in the hill valleys and plains of U.P. and it is a serious threat to mango production its severity mainly depends on climatic conditions. The losses have been estimated up to 20% in maharastra and 30-90% in Lucknow and U.P
    Symptoms
    • A whitish powdery growth covers the stalks of the panicle, flowers and tender fruits.
    • The whitish growth of the fungus comprising of asexual fruiting body an oidea.
    • The affected flowers and fruits drop prematurely reducing the setting of fruits.
    • At higher altitudes, the infection extends to the young leaves and twigs.
    • Many of these are covered by the white powdery fungal growth and may exhibit distorted growth. On younger leaves it induces leaf curling.

    Powdery mildew on leaves and flowers

    Figure Courtesy: A. http://www.ctahr.hawaii.edu/nelsons/mango/, B. http://www.hort.purdue.edu/ext/senior/fruits/images/large/mangolvs2.jpg and C. http://www.infonet-biovision.org/default/images/81/pests

    Etiology

    • Oidium mangiferae, Berthet. It produces septate mycelium and is hyaline, branched and superficial. Haustoria are sub epidermal.
    • Conidia are hyaline, unicellular, elliptical and are borne singly or rarely in chains

    Mode of spread and survival

    • During off-season, the pathogen survives in the intact green malformed panicles mostly hidden under dense foliage and its sexual forms has not been recorded.
    • During flowering period, the conducive environmental condition activates the dormant mycelium in necrotic leaves.
    • Abundant conidia are produced and blown over to the new flushes through the wind on young panicles which provides spore load for initiating the disease.
    • Fresh infection on young leaves happens during first week of the December.

    Epidemiology

    • It usually occurs during Dec-Mar. The disease is particularly destructive in the coastal areas of maharastra during cold and wet seasons.
    • Rains or heavy mist in the morning accompanied by cool nights during the flowering period favors the disease.
    • Predominance of susceptible variety, high wind velocity for 3-4days with maximum temperature above 300c, minimum temperature around 150c and maximum relative humidity of 73.3-83.9% and minimum of 23.4-25.5% are found conducive for quick spread.

    Management

    • The disease can be managed by pruning of diseased leaves and malformed panicles and three sprays of fungicides at different stages starting with Wettable Sulphur (0.2%) at the panicle size of 7.50 -10.00 cm followed by Dinocap (0.1%) after 15-20 days of first spray and Tridemorph (0.1%) after15-20days of second spray.
    • Wettable Sulphur (0.2%) can be used in all the three sprays and number of sprays may be reduced as per appearance and time of disease.

Last modified: Friday, 22 June 2012, 4:44 AM