Soya

Disease Management

Bacterial Pustule Myrothecium Leaf Spot Rust Yellow Mosaic Soybean Mosaic

Bacterial Pustule

    • This disease caused by Bacteria Xanthomonas campestris pv.glycines.
    • It develops during warm and wet weather.
    • The disease spreads rapidly in rainy conditions.
    • It is seed born.
    • The disease causes upto 18% losses to the Soybean crop and is responsible for early yellowing and defoliation.

    Symptoms

    • Small yellowish green pods with reddish brown centres are formed on the upper surface of leaves.
    • The central portion of the individual spot appears slightly raised.
    • Small pustules are found on the under side of the leaves.Similar pustules also occur on pods.
    • The pods may merge to produce large irregular dead areas.
    • The dead tissue sometime may rupture and tear away. Heavily infested leaves turn yellow and fall and in susceptible plants complete defoliation can occur.
    • The bacterium survives in crop debris and seed.

    Control Measures

    1. Grow resistent varieties.
    2. Seed treatment with carboxin @ 0.2%
    3. Spray Mancozeb (Dithane M-45) @ 0.2% or Copperoxy chloride + Streptocycline @ 0.15% + 200 ppm, respectively.

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Myrothecium Leaf Spot

    • The disease is caused by Myrothecium roridum Tode ex Fries.
    • It used to be miner disease earlier.
    • Recently it has acquired a major proporition.
    • The disease spreads rapidly under rainy conditions, it is more severe during warm and wet weather.
    • The disease is likely to cause 20-40% yield losses to the soybean crop.

    Symptoms

    • Small round or oval,brown,spots develop with dark brown or purple margin on leaves in the infected plants.
    • Trasluscant areas develop around these spots which appear as concentric rings.
    • Later on dark green sporodochia develop in these areas.
    • The symptoms may appear on the other aerial parts, such as stem, petiole, pods etc, also.
    • The spots may merge to form irregular shape and leaves become dry.
    • The pathogen survives in crop derbris and seed.

    Control Measures

    • Use healthy and certified seed.
    • Remove diseased plant debris.
    • Treat the seed with Thiram or Captan @ 3-4 g/kg seeds.
    • Spray Mancozeb (Dithane M-45) or Zineb (Dithane Z-78) @ 2.0-2.5 kg/ha in 1000 litre of water at 10-14 days intervals. 2-3 sprays are enough for controlling the disease.

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Rust

  • This is caused by Fafopsora Pachairaisi.
  • This is found in North East pods of India

Symptoms

  • In the beginning, brown spots are seen on the leaves.
  • Afterwards, they covered the whole leaf. Brown coloured powder is found on leaves and after sometime whole leaf turns brown.

Control Measures

  • Resistent varieties
  • Spray Mancozeb (Dithane M-45) @ 2.5 kilogram per hec.
  • Solution should be made in 1000 ltrs of water and should be spread 2 to 3 times with 10 days intervals.

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Yellow Mosaic

  • It is caused by mung bean yellow mosaic virus (MBYMV).
  • This virus is most damaging and can cause serious yield losses.

Symptoms

  • Characteristic symptom is conspicuous systemic bright yellow mottling of leaves.
  • The yellow area are scattered or occur in indefinite bands along the major veins.
  • This virus has a wide host range and is not sap or seed transmissible.
  • Insect vector for MBYMV is whitefly. (Bemisia tabaci).
  • If the plant is infected wthin 75 days after planting, the yield reduction are significant but infection after 75 days results non-significant yield losses.

Control Measures

  • Grow resistent/tolerant varieties
  • Rogue out infected plants and burn them.
  • Use regular insecticidal spray i.eMetasystox 25 E.C.@ 0.1%

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Soybean Mosaic

    • It is caused by Soybean Mosaic virus.
    • The SMV can be transmitted through sap,aphids and seed

    Symptoms

    • Deseased plants are usually stunted with distorted (puckered, crinckled, ruffled, stunted, narrow) leaves.
    • The parts are often stunted.
    • Flattened or curved and contain fewer and smaller seed.
    • Infected seeds fail to germinate or they produce diseased seedlings.
    • The virus over-seasons in living plants and spreads by sowing virus-infested seeds.

    Control Measures

    • Sow virus free seeds from SMV free fields.
    • Keep down weeds and aphid population.
    • Rogue out infected plants and burn them.
    • Grow resistent cultivars.

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Andhra Pradesh

Soya

Soya Management