DISEASES OF MINOR MILLETS

DISEASES OF TENAI – திணை

1. BLAST – Pyricularia setariae

Symptoms

The spots present on the leaf blade are circular with light centre and are surrounded by a dark brown margin. Finally the infected leaves wither and dry up.

Mode of spread

The pathogen spreads through air borne conidia

Survival 

The pathogen survives in the infected plant debris and collateral hosts.

Epidemiology

High RH, low night temperature and cloudy weather favours the disease development 

Management

• Seed treatment with captan or thiram @ 4 g/kg or carbendazim 2 g/kg of seed
• Spray the crop with Iprobenphos or edifenphos at 500 ml/ha

2. LEAF SPOT/LEAF BLOTCH – Helminthosporium setariae

Symptoms

Spots of varying sizes viz., small, large and brown coloured are formed on the leaves. Lesions also appear as blotches and rotting of the secondary roots also occurs.

Mode of spread

The pathogen is externally seed borne

Survival  

The pathogen survive in the infected seeds

Epidemiology

A temperature of 30⁰ C is ideal for the disease development

Management

• Seed treatment with captan or thiram @ 4 g/kg of seed

3. SMUT – Ustilago crameri

Symptoms

Symptoms appear at the time of flowering. The normal grains are replaced by large, spherical sori which are grayish white in colour containing black mass of spores

Mode of spread

The pathogen spreads through air borne chlamydospores

Survival  

The pathogen survive in the infected seeds

Epidemiology

Low temperature and high humidity favour the disease

Management

• Seed treatment with captan or thiram @ 4 g/kg of seed
• Grow resistant varieties like NO 2, 18, 36

4. DOWNEY MILDEW/GREEN EAR- Sclerospora graminicola

Symptoms

Primary infection causes chlorosis of the plant and the leaves turn whitish. The terminal spindle fails to unroll, become chlorotic and later turn brown and the spikelets are converted to filamentous leafy structures

Mode of spread

The pathogen spreads through wind borne conidia

Survival 

The pathogen survives in the soil as oospores

Epidemiology

High humidity, rainy weather, low temp.,and high soil moisture favour the disease

Management

• Seed treatment with captan or thiram @ 4 g/kg of seed
• Spray with zineb @ 0.2 %
• Grow resistant varieties like China Tsiman, Tenai strains no. 18, 02 and 36

DISEASES OF KUDIRAIVALI

1. SMUT- Ustilago crus-galli

Symptoms

The fungus produces gall – like swellings on the stem, nodes of young shoots and axils of older leaves. The gall – like swellings are covered by a tough hairy membrane of the host tissue

Mode of spread and Survival 

The pathogen is externally seed borne and survives in the infected seeds

Epidemiology

Low temperature and high humidity favour the disease

Management

• Seed treatment with captan or thiram @ 4 g/kg of seed

DISEASES OF VARAGU / KODO MILLET

1. HEAD SMUT – Sorosporium paspali-thunbergii

 Symptoms

The entire panicle is transformed in to a long sorus and a young cream coloured thin membrane covers the sorus. Later the membrane bursts open and exposes the black mass of spores

Mode of spread and survival

The pathogen is seed borne and survives in the infected grains

Management

• Seed treatment with captan or thiram @ 4 g/kg of seed

2. ERGOT /SUGARY DISEASE – Claviceps paspali

Symptoms

Rarely drops of honey – dew ooze out from the infected spikelets. Later, when the ears mature, dark grey sclerotia are formed in the spikelets 

Mode of spread

Pathogen spreads through air borne ascospores

Survival 

Infected plant debris 

Epidemiology

High rain fall and humidity favour the disease

Management 

• Removal and destruction of the infected ears

DISEASES OF PANIVARAGU / SMALL MILLET

1. RUST – Uromyces linearis

Symptoms

Numerous, narrow, minute, brown pustules arranged in linear rows appear on the upper urface of the leaves

Mode of Spread And Survival 

The pathogen spreads through air borne uredospores and survives in the infected plant debris

Epidemiology

Low temperature and low relative humidity favour the disease

Management 

• Seed treatment with captan or thiram @ 4 g/kg 

DISEASES OF SAMAI

1. SMUT- Sphacelotheca destruens

Symptoms

The entire inflorescence is converted in to a sorus containing spores and fibrous vascular bundles. The sorus is covered by a white or grey membrane. Also abnormal development of hairs on the leaf sheath can be seen in the infected plants

Mode Of Spread And Survival 

The pathogen is seed borne and survives in the infected plant debris

Epidemiology

Low temperature and high relative humidity favour the disease

Management

• Hot water treatment at 55⁰ C for 7 – 12 minutes

 I2.DOWNEY M LDEW- Sclerospora graminicola

Symptoms

Long, yellow stripes appear on the leaves. Later the leaf tissues shred and the leaves dry. Entire plant dries up before flowering and produce only chaffy grains  

Mode of Spread and Survival 

The pathogen spreads through Wind borne and survives in soil as oospores

Epidemiology 

Rainy season and humid condition favour the disease

Management

• Seed treatment with captan or thiram metalaxyl @ 4 g/kg of seed