1) The document discusses several diseases that affect brinjal/eggplant crops including little leaf caused by phytoplasma, bacterial wilt caused by Ralstonia solanacearum, and Phomopsis fruit rot caused by Phomopsis vexans. 2) Little leaf results in small, stunted leaves and bushy growth while bacterial wilt causes sudden wilting and death. Phomopsis causes fruit rot and blight on leaves and stems. 3) Diseases spread through vectors like jassids for little leaf and are managed through resistant varieties, crop rotation, and fungicide/insecticide sprays.

1. DISEASES OF BRINJAL
HPP 5311 3(2+1)
Diseases of vegetables, ornamental
and spice crops

2. Little leaf
Pathogen
Phytoplasma
• The disease is caused by Phytoplasma having ovoid to spherical
body which is concentrated in the phloem sieve tubes.

3. Symptoms
• Small or little leaves.
• The petioles are so short that the leaves appear to be sticking to the
stem.
• Affected plants have narrow, soft, smooth and yellow shorter leaves.
• Newly formed leaves are much shorter.
• Internodes of the stem are also shortened.
• Axillary buds get enlarged but their petioles and leaves also remain
shortened giving the plant a bushy appearance.

4. • Mostly there is no flowering
but if flowers are formed they
remain green.
• Fruiting is rare, if any fruit is
formed, it becomes hard, tough
and fails to mature.
• Young fruit turns necrotic, get
mummified and cling to the
plant

5. Spread
• The pathogen perenneates in weed hosts.
• Jassid - Hishimonas phycitis. The disease is also transmitted by
Emposca devastans, however, it is a less efficient vector.
• The varieties pusa purple long and selection T are highly
susceptible.
• Collateral hosts: Datura fastuosa, D. stramonium, Vinca rosea,
Argemone mexicana, chilli, tomato and tobacco.

6. Disease cycle

7. Management
• Tolerant variety: Pusa Purple Round, Pusa purple cluster and
Arka sheel
• Destruction of affected plants.
• Eradication of solanaceous weed hosts.
• Spray methyl demeton, 2 ml/l or soil application of phorate
granules.
• Seed dip in tetracycline (10-50 ppm).

8. Bacterial wilt
Pathogen:
Ralstonia solanacearum
• The bacterium is Gram negative motile, rod, having rounded
ends with 1-4 polar flagella.
• Race 1 of R. solanacearum affects solanaceous plants such as
tomato, egg plant and many other non-solanaceous plants also.

9. Symptoms
• Sudden wilting and death of infected
plants is the characteristic symptom.
The petiole of older leaves droop
down and the leaves show epinasty
symptoms accompanied by yellowing
and stunting of whole plant.
• Typical browning of vascular tissues
of roots and stems can be seen.
• From cross sections of infected plants
whitish bacterial exudate comes out.

10. Mode of survival and spread
• The bacterium is both soil and seed borne in nature and overwinters
in infected plant parts, in wild host plants and weeds.
• Spread through irrigation water or infested soil and agricultural
implements.

11. Disease cycle

12. Favourable conditions
• Relatively high soil moisture and soil temperature favour the disease
development.
Management
• Grow resistant varieties like Pant Samrat, Arka Nidhi, Arkas
Kashav, Arka Neelakantha, Surya and BB 1, 44 & 49.
• Crop rotation with non solanaceous hosts
• Green manuring with Brassica species (Biofumigation)
• Soil solarization with a transparent polyethylene sheet (125 μm
thick) for 8-10 weeks during March-June
• Biological control with Pseudomonas fluorescens, P. glumae, P.
cepacia, Bacillus sp. & Erwinia sp.

13. • Nursery application: Treat the seeds with talc based formulation of
antagonistic Pseudomonas f1uorescens (1Og/1OOg of seeds) and
soil application of antagonistic P. f1uorescens (50g mixed with one
kg of soil and incorporated in the nursery bed).
• Main field treatment: Dip the seedlings in the antagonistic P.
f1uorescens/ B. subtilis (@ 259 talc formulation per litre of water)
solution for 20-30 minutes just before transplanting. The left-over
solution should be drenched around the root zones (50ml/plant).

14. Phomopsis fruit rot or blight
• The disease is severe in tropical and sub-tropical areas of the world. In
India, it was reported in 1935 in Gujarat. The pathogen attacks foliage and
fruits, but the latter phase is more destructive.
Pathogen:
• The mycelium of the pathogen is septate and hyaline becoming
dark with age.
• Pycnidia are submerged and later becoming erumpent with a
prominent ostiole.
• Conidia are produced on simple to branched conidiophores and are
of 2 types: Alpha conidia, which are sub cylindrical and beta
conidia, which are filiform and curved.
• Role of beta-conidia in the epidemiology of the disease is not very
clear. The perfect stage produces perithecia in which asci with 8
hyaline, bicelled, ellipsoid-fusoid ascospores are produced which are
usually constricted at septum.

15. Symptoms
• The plants are attacked at all stages of growth, producing damping-
off symptoms in nurseries and collar rot on young plants.
• On leaves, circular to irregular, clearly defined grayish brown spots
having light centers appear. The diseased leaves become yellowish
in colour and may drop off. Several black pycnidia can be seen on
older spots.
• The lesions on stem are dark brown, round to oval and have grayish
centers where pycnidia develop. At the base of the stem, the fungus
causes characteristic constrictions leading to canker development
and toppling of plants.

16. • On fruits, small pale sunken spots appear which on enlargement
cover entire fruit surface. These spots become watery leading to soft
rot phase of the disease. A large number of dot like pycnidia also
develop on such spots.
• The infection of fruit through calyx leads to development of dry rot
and fruits appear black and mummified.

17. Mode of survival and spread

18. • The pathogen is seed borne and also survives in plant debris both as
mycelium and pycnidia.
• Seed infections directly lead to diseased seedlings.
• The pycnidiospores are disseminated through rain splashes,
irrigation water, agricultural implements and insects.
OR
• P.I: Pathogen is seed borne and also survives in plant debris as
mycelium and pycnidia.
• S.I: Conidia dispersed through rain splashes, irrigation water,
agricultural tools and insects.

19. Favourable conditions
• High relative humidity coupled with higher temperatures favour
disease development.
• Maximum disease development takes place at about 26⁰C under wet
weather conditions with 55% R.H.

20. Management
• Removal and destruction of diseased crop debris.
• Practicing crop rotation and summer ploughings helps in reducing
initial inoculum.
• Use of disease free seed
• Hot water treatment of seed at 50⁰C for 30 minutes.
• Seed treatment with thiophanate methyl at 1g/kg seed.
• Spray twice with thiophanate methyl or carbendazim@0.1% at 20
days interval.

21. Cercospora leaf spot
• Several leaf spot diseases affect this crop but the leaf spots caused
by Cercospora species are important which under high humidity
conditions cause considerable yield losses.

22. Symptoms
Cercospora melongenae
• The symptoms of the disease appear as circular to irregular leaf
spots, which are usually large and brown to grayish brown in colour.
• Later spots coalesce together and affected leaves fall down
prematurely and sometimes fruits may rot.

23. Disease cycle
• The fungus survives from one season to another in infected plant
debris in soil and also in infected seeds wherever fruit rot occurs.
• Warm days and cool nights are ideal for the infection.
• The disease is favoured by high humidity and heavy persistent dews.
• Water droplets must be present for spore germination and germ-tube
penetration.
• Moist wind, irrigation water and insects help in local transmission of
the pathogen.

24. Management
• Cultural practices like destruction of crop debris, crop rotation, use
of disease free seeds and wider plant spacing should be followed to
reduce the primary inoculum of the pathogen in field.
• With the initiation of the disease spray the crop with zineb (0.25%),
carbendazim (0.1%) or thiophanate methyl (0.1%) and repeat at 10
to 14 days interval.