Diseases Of Pearl Millet

By TamilNadu Agricultural University on 07 Nov 2016 | read

1. Downy mildew or Green ear

Causal organism : Sclerospora graminicola

Symptoms: Two stages (i) Downy mildew stage (ii) Green ear stage

Downy mildew stage: Affected leaf exhibits white downy growth in patches on its lower surface. These patches expand and cover the entire lamina which turns yellow in due course. The downy growth consists of sporangiophores and sporangia.

Green ear stage : The ear heads are converted into green leafy structureseither partially or fully. The oospores serve as primary source ofinoculum.

Favourable Conditions :Very high humidity (90%);Presence of water on the leaves; Low temperature of 15-25˚C favor the formation of sporangiophore and sporangia.

2. Rust

Causal organism: Puccinia penniseti

Symptoms: Infection is seen in the form of brownish yellow pustules on both the leaf surfaces. These represent the uredia of the fungus.Teliosori are black and seen on leaf and leaf sheath. Brinjal is the alternate host.

Favorable Conditions : Closer spacing ;Presence of abundant brinjal plants and other species of Solanum viz., S.torvum, S. xanthocarpum and S. pubescent.

3. Smut

Causal organism : Tolyposporium penicillariae

Symptoms: The disease becomes apparent at the time of grain set. A few grains, sporadically distributed on the ear head are replaced by green to black sori, which are much bigger than normal grains. The soruswall is tough, surrounding the powdery mass of smut spores which are in balls.

Favorable Conditions : High relative humidity; Successive cropping with pearl millet

4. Ergot / Sugary disease

Causal organism: Claviceps fusiformis

Symptoms: Small droplets of pinkish sticky fluid oozes out of thespikelets. The affected spikelets turn black and several such dark sticky patches are seen on the ear head. Grain formation is inhibited. The honeydew contains large number of hyaline single celled conidia. Later infected ovaries get converted into sclerotia.

A. Management of pearl millet diseases

1.Seed treatment

Removal of ergot / sclerotia to prevent primary infection

Dissolve 1 kg of common salt in 10 liters of water. Drop the seeds into the salt solution. Remove the ergot and sclerotia affected seeds which will float. Wash seeds in fresh water 2 or 3 times to remove the salt onthe seeds. Dry the seeds in shade. Treat the seeds with Thiram @ 2g /kgof seed. Treat the seeds with Metalaxyl 6g/kg for the control of downy mildew in endemic areas

2. Downy Mildew: Sclerospora graminicola

Grow downy mildew resistant varieties CO7, WCC 75, CO(Cu)9,

TNAU-Cumbu Hybrid-CO9 Transplanting reduces disease incidence. At the time of planting infected seedlings should be removed.

In the direct sown crop, infested plants should be removed up to 45 days of sowing as and when the symptoms are noticed.

Spray any one of the fungicides

Metalaxyl + Mancozeb @500 g or Mancozeb 1000g/ha

3.Rust: Puccinia penniseti

Sowing during December - May result in less incidence.

Adopt control measures when there is rust incidence in the early stages as spread of infection to top leaves results in poor grain filling.

Spray any one of the following fungicides when the initial symptoms ofthe diseases are noticed.

Wettable sulphur 2500g / ha

Mancozeb 1000g/ha

Repeat application 10 days after if necessary.

4.Sugary or Ergot disease: Claviceps fusiformis

Spray any one of the fungicides like Carbendazim 500g or Mancozeb1000g /ha when 5 - 10% flowers have opened and again at 50%flowering stage.

B.Integrated management strategies for major pest and diseases ofpearl millet

Seed treatment with Metalaxyl @ 6g/kg of seeds + Seed treatment with Imidacloprid @ 5g/kg of seeds + Removal of downy mildew infected plants up to 45 days of sowing + Spraying of Mancozeb @ 1000g/ha +Spraying of NSKE 5% @ 50% flowering against downy mildew, rustand shoot fly.