3 Crops of Cereal and their Main Diseases

What will be covered?• What is Barley?– Powdery Mildew – Covered Smut– Loose Smut

• What is Millet? – Green ear or downy mildew – Grain smut – Ergot

• What is Maize?– Smut – Common Rust– Leaf Blight

Barley

• Barlay is a member of the grass family and a major cereal grain

• It is used as a component of various health foods, soups and stews, and in barley bread of various cultures

• Barley is cultivated on a small scale in Pakistan

Powdery Mildew

• Pathogen: Blumeria graminis• Symptoms:– can be found on leaves, stems and ears – white pustules appear eventually become

black spore (cleistothecia) towards the end of the season

Life Cycle

Covered Smut Loose Smut

• Pathogen: Ustilago hordei• Symptoms:

– Ear emergence – In which ears seem to be

normal but grains appear to be covered in a thin membrane

– Grains have been replaced by masses of black spores

– Membrane is easily ruptured and as spores are released the symptoms become similar to those of loose smut

• Pathogen: Ustilago nuda • Symptoms– Ear emergence – Replaced by a mass of

black fungal spores– The spores are released as

soon as the ear emerges, leaving only the bare remains of the ear rachis

– Blackened ears are so obvious in the crop at ear emergence the disease appears to be very severe

Life Cycle

Millet

• Grown under erratic distribution of annual rainfall, high mean temperature and depleted soil fertility

• These are currently the fourth cereal in Pakistan

• It is mostly confined to the desert and mountain (Thar-Cholistan and Kohistan) area

Green ear or downy mildew

• Pathogen: Sclerospora graminicola• Symptoms: – Ear formation stage– Leaves become distorted, twisted, crinkled and

lose their green colour, become white and later turn brown

– The ears are transformed in to green leafy structures with enlarged glumes, turning wholly or partially into loose heads

– The affected portions are sterile and they do not produce grains

Life Cycle

Grain smut

• Pathogen: Tolyposporium penicillariae• Symptoms: – Infected grains are thickened, slightly elongated– Covered by tough and blackish green membrane

filled with fungal spores– These are present singly or in groups – Usually a one side of the ear or towards its base – Scattered or collected together in patches on the

ear

Life Cycle

Ergot

• Pathogen: Claviceps purpurea• Symptoms:– The causal fungus only attacks the ear at

flowering, replacing the grain in a few spikelets by a hard, purple black sclerotium, known as an ergot

– Such ergots can be very large, up to 2cm in length

Maize

• Cultivated as multipurpose food and forage crop, generally by resource poor farmers using marginal land

• In Pakistan, it is the third most important cereal after wheat and rice

• An important crop in Pakistan in terms of its food for human, feed for poultry and fodder for livestock utilization and as a raw material for the industry

SMUT

• Pathogen: Ustilago maydis• Symptoms: – White to grayish-white galls (soft tumors) develop

on any part of the plant. – These galls are light coloured in early stages,

become blackish on maturity and filled with black powder

– Large sized galls involving the entire head

Rust

• Pathogen: Puccinia sorghi• Symptoms: – Recognized by small, elongate, powdery pustules

over both surfaces of the leaves – Pustules are dark brown in early stages of

infection; later, the epidermis is ruptured– Lesions turn black as the plant matures

Anthracnose leaf blight

• Pathogen: Colletotrichum graminicola• Symptoms: – The disease is present in warm, humid environments

with a foliar disease phase and a stalk rotting phase.– The most severe damage is caused by the stalk rot

phase. – Foliar damage can be observed at different stages of

plant development• In the early seedling stage, leaves show irregular, oval-to-

elongated lesions with characteristic yellow-to-reddish-brown margins

• In later stages of plant development, similar lesions can be observed in the upper leaves of infected plants, especially in those where stalk rot symptoms have already developed

Control:

• Use resistant varieties • Use Fungicide seed– Always have new seed treated with fungicide

• Spraying with a foliar fungicide• Field sanitation• Do not sow diseased seed• Collection and burning of diseased plants or

plant parts, as soon as they appear• Use of 2-3 year crop rotation