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Rice In Sri Lanka - Rice Diseases

False smut

Causative agent

Fungus, Ustilaginoidea virens

Plant parts and life stages affected

Mature panicle and grains

Symptoms

This disease is considered as an omen of a good harvest, as the factors that favour this disease will also favour a good yield.

Disease symptoms start to show when the grains get mature. When the grains are full, the pericarp splits a little bit, which facilitates the causative agent to enter and develop.

Seed coat remains green while inside the grain, the disease develops forming a large orange to brown-green fruiting structures

This could be observed in one or more grains of the mature panicle.

Later the orange covering ruptures exposing a mass of greenish-black spores

The grain is then replaced by one or more sclerotia.

 

Conditions that favour the disease

Environmental temperatures within 25-35 OC

High humidity

Rain and winds during flowering stage

Excessive use of nitrogen fertilizer

Higher plant density

Weeds

Susceptible varieties

            Bw 367, Bg 403

Disease Management

Within the crop season

Application of urea in recommended dosages or application of urea based on leaf colour chart.

Water management

If the crop is infected, following management options should be applied for the next season

Use of certified seed paddy free from the disease

Weed management

Addition of burnt paddy husk (253 kg per acre) to the soil during land preparation.

Abstain addition of straw infected with disease

Water management

Maintaining an average level plant population in the field