Maize, Millet and Sorgham Diseases & Management

1. Seed and seedling Diseases

Symptoms

  • Sick Seed does not grow properly
  • If the some seeds grow, the plant wilt and necrosis of plant occur.
  • Wilting of newly grown plants occur mostly in the early growing crops.

Treatment

  • Use of resistant varieties.
  • Seed treatment with Toprin-M @ 2gm/kg of Seed.

i. Leaf Blight of Maize

Symptoms

  • The Disease appears first on lower leaves and then spread on all the leaves.
  • Brown oval shaped spots are produced which spread rapidly at 25-30C0.
  • In Punjab, the disease attacks on the crop near maturity.

Treatment

  • Spray the fungicide Dithan M-45 @ 500gm / acre or Benlate 500gm/acre.
  • Destrray the plant disease debris of previous crops.

ii. Stalk Rot

Symptoms

  • Plants start rottening from the 2nd internodes, leaves turn pale, dry up and plants fall on the ground.
  • When infected stalks are split, the phloem appears dark brown and there is browning of tissues and pith is shredded off.
  • Cobs droop down, grains of the cobs remain small which reduce production

Treatment

  • Seed treatment with Toprin-M @ 2gm/kg of seed.
  • Use of resistant varieties.
  • Ridge sowing also reduces the diseases.

iii. Ear Rot

Symptoms

  • Many fungi cause ear rot.
  • Infected kernels develop a cottony growth.
  • Sometimes light blue green or black powder grows between the kernels or on the cob surface.

Treatment 

  • Use of resistants varieties or hybrids.
  • After harvesting of the crop, remaining parts of plants should be destroyed.
  • Moisture %age should not more than 12% when cobs are stored in gowdams.

2.  Pearl Millet / Bajra

i. Green Ear Disease of Bajra

Symptoms

  • The diseased plant show the symptoms of stunting and malforonation (no grains) of floral parts.
  • The ears remain small and twisted leaf like structures are produced in the ears which are green in color
  • The glumes, stamens and pistils are replaced by leafy shoots and there is no formation of any grain.
  • The diseased plants remain dwarf due to reduction of internodes.

Control

  • Seed treatment with different fungicide e.g. Toprin-M @2gm/kg of seed or benlate @ 2gm/kg of seed.
  • Use of resistant varieties.

ii. Sumt of Pearl Millet

Symptoms 

  • The disease attacks the plants from leaves to heads.
  • Due to the attack of disease, the grains in the heads are converted into black powdery mass and the yield is affected badly.

Control

  • Use resistant varieties
  • Sow the seeds after treatment with feticide e.g. Toprin-M @ 2gm/kg of seed.

iii. Rust of Pearl Millet

Symptoms 

  • This disease attacks on the leaves of the plants.
  • The disease spots can be easily seen on the leaves.
  • The disease inhibits the process of photosynthesis due to which growth of the plants is badly affected and ultimately the yield is reduced. 

Control

  • Use resistant varieties
  • Sow the seeds after treatment with fungicides e.g Toprin-M @ 2gm/kg of seed

3. Downy Mildew of Sorghum

Symptoms

  • Affected seedlings have pale yellow narrow leaves.
  • Leaves are shredded off.
  • The plants remain stunted and sterile.
  • No ear formation, if ears are produced those are of small size.

Control

  • Crop rotation
  • Use of resistant varieties
  • Destruction of plant disease debris.

i. Rust of Sorghum

Symptoms

  • Bright purplish, red spot appear on the surface of the leaf especially on the underside of leaf.
  • Small brown or reddish uredo-postules appear on the leaves.
  • These uredia are elongated & parallel to veins.

Control

  • 4-5 application of navam and zinc sulphate starting from the stage of infestation.
  • Some antibiotics are also suitable but not practicable to cover large areas.

ii. Grain Smut of Sorgham

Symptoms

  • Ovaries are attacked.
  • Ovaries in an infected ear are formed into smut sorus.
  • Generally the ovaries are replaced by dirty grey sac of smut sorii.

Control

  • Seed should be treated with fungicide before sowing.
  • Organic mercuric compounds are suitable.
  • Sulpher dusting is also effective.