Wel Come

1. Downy mildew / Green Ear head disease.

2. Ergot or sugary disease.3. Smut disease.4. Rust disease.

DISEASE OF PEARLMILLET (BAJRA).

C.O. – Sclerospora graminicolaClass – OomycetesOrder –peronosporalesFamily – peronosporaceaeOther synonyms : Jogida,Bawa,Kutul,Witches

broomFirst Report :India – E.J.Butler (1907)Yield loss : 30 % yield loss was reported in high

yielding veritiesSymptoms : The downy mildew appears in two

distinct phases.

1. Downy mildew / Green Ear head disease.

The infected plants tiller excessively.Dwarfing and shortening of internodes.The foliage becomes pale and chlorotic.Broad chlorotic streaks extending from base

to the tip of leaf observed.Downy fungal growth can be visible on lower

surface of leaf and in severe cases it may appear on upper surface.

Chlorotic yellow streaks turn brown and leaf become shredded lengthwise.

1. Seedling stage

When the pathogen infect the host systemically , ear head become malformed.

Entire ear head is transformed in to leafy structure the floral plans glumes, palea , stamens and pistil converted into leafy structure.

The leafy structure becomes brown and dry up without grain formation .

In some cases partial grain filling is observed.

2. Green ear head stage

Downey mildew disease

The pathogen is obligate parasite , produces oospores which remain viable in soil for five year and after germination which can cause primary infection in seedlings. Secondary spread starts from sporangia and zoospore which are most active during rainy season. The germ tube of zoospore enters the leaf stomata to initiate infection . After infection the pathogen produce intercellular aseptate mycelium .

Disease cycle

Other Host : - Setaria italic The bajra and setaria italic races do

not infect their host reciprocally, but both readily can infect teosinte.

 Favourable Condition :High humidity < 90 % .Presence of water on leaves.Low atmosphiaric temperature 15 -

25 C.

Crop rotation with non host crop. Collect diseased plants and destroy them.Early sowing of bajra on onset of monsoon for

escaping disease.Treat the seeds with apron 35 SD @ 6 g / kg seed

or fosetyle @ 5 g / kg seed.Two –three sprays of metalaxyl compound

( ridomil MZ 72 WP ) @ 4 g / 10 lit water .Spray mancozeb 1 kg / ha , 20 DAY.Use resistance varieties – : GHB -15 , PHB –10 ,

MH-169 , HB-1 , HB-5 , PHB-14 , MH-179 , CO-7.

Management

C.O. – Cleviceps microcephalaClass – AscomycetesOrder – HypocrealesFamily – HypocreceaeDisease appeared in epiphytotic

from during 1967-68 in Maharastra and Karnataka states.

Distribution : Africa and India

2. Ergot or sugary disease.

Ergot or sugary disease

Disease appear only at flowering stage.Exudation of small droplets of light pinkish or

brownish sticky fluid ( honeydew ) from the infected spikelets.

Under sever infection , many such spikelets exude plenty of honeydew , which trickle long the ear head .

Honeydew attracts the insects which helps in secondary spread of disease in the field .

The infected ovaries darken with age small grayish dark brown sclerotia are formed .

The sclerotia contain the alkaloid ergotin , which cause nervous break down in human being and animals .

Symptoms

High rainfall and high humidity during flowering.

Cool weather.Remove of collateral host of disease .

Favourable condition

The primary source of inoculum is sclerotia , which helps the pathogen to perpetuate from season to season. The sclerotia either remain in soil or mixed with or in infected debris. They germinate and cause primary infection through ascospores in the spikes producing the conidial stage. The honeydew secretion attracts the insect for feeding and the conidia are disseminated in the field through insects causing secondary spread of the pathogen.

Disease cycle :

The fungus infects the grass cenchrus ciliaris and cenchrus setigeurs

Collateral host :

Removal of collateral hosts .Use disease free seeds.Sowing crop just after on set monsoon.Seed treatment with 20 % brine soluction

(Nacl) to separate out sclerotia from the seeds. Dry the seeds in shade and store.

Spraying of carbendazim 300 g or mancozeb 1.25 kg / ha when 5-10 % flower have opened and second spray at 50 % flowering.

Management :

C.O.- Tolyposporium penicillariae Class – BasidiosporeOrder – UstilaginalesFamily – UstilaginaceraeDistribution : Pakistan , Africa and India In India : prevalent in Tamil Nadu , Andhra Pradesh ,

Maharastra and Gujarat.

3. Smut disease.

Smut disease

Disease becomes apparent at the time of grain setting.

Pathogen infects few florets and transforms them into black spore containing smut spore.

The infects sori larger and greater then normal healthy grains and they are bright green to dirty black in colour.

When the sori are ruptured , it releases millions of black smut spore balls.

Symptoms :

Favourable condition :High humidity.Successive cropping with bajra.

Disease cycle : The infection starts mainly from air-borne

spore , which germinate to produce the sporidia , which enter the spikelets and infect the ovary . The spore balls remain in soil to germinate during the next season , producing masses of sporidia , which becomes air borne and infect the ear.

Removal of smutted ear-heads & destroy them.

Use clean , healthy disease free seeds.Follow crop rotation with non-host crop.Grow bajra in summer season.Sowing the crop before 15 th july found most

suitable in reducing downy mildew , eargot & smut disease.

Management :

4. Rust disease.

C.O.- Puccinia pennisetiClass – Basidiomycetes

4. Rust disease

The minute round uredospore occur in group on both surface of leaves , particularly towards the distal end of the blede , on the leaf sheath & stem.

The telia which appear later in the season are black elliptical and sub epidermal and are also distributed over the leaf blade , leaf sheath and stem. In severe infection , the plant appear unhealthy and slightly stunted compared with non infected once.

Symptoms :

The rust fungus is heteroceous and alternate host of the rust fungus is brinjal.

Uredospore are known as repeating spore and cause infection in field.

Disease cycle

Use resistant varieties.Two spray of mancozeb or zineb @ 0.2 at 15

days interval starting from initial stage infection .

Removal of alternate host grasses.Use of bio-control with fusarium sanbycium ,

f. roseum , f. semifectum. Immediately sowing after on set of monsoon.

Management