Root knot nematodes and reniform nematodes are major pests affecting brinjal and tomato crops. They weaken plant growth and make roots more susceptible to disease. On tomato, they cause stunting, pale leaves, and root galls. On brinjal, symptoms include stunting, leaf yellowing, and root lesions or galls. Management includes crop rotation, soil solarization, marigold planting, and soil additives like neem cake or Pseudomonas fluorescens to reduce nematode populations in the soil. Nematode-resistant tomato varieties are also recommended.

1. Nematodes on Tomato
&
Brinjal

2. Nematode on tomato

3. DISEASE
 Several species of root knot nematodes cause a stunting and
wilting of many vegetables and ornamentals, including tomato,
potato, eggplant, sweet potato, radish, geranium, and peony.
 The disease typically appears in roughly circular patches in a
field or garden, but may become more uniformly distributed
when susceptible plants such as tomato are continuously
planted in an area.
 Diseased tomato plants are stunted and have pale green leaves.
 Diseased plants also may show symptoms of nitrogen,
potassium, or phosphorus deficiencies even though adequate
levels of these minerals are in the soil.

4. ….Cont
 The most characteristic symptoms of the disease occur below
ground.
 Roots develop multiple small tan galls.
 These galls often fuse to cause extensive swelling and
distortion of the root system.
 Injury to the roots affects the uptake of water and minerals.
 The roots also become much shorter and bushier than on
healthy plants.

5. Root galls and swelling caused by
root knot nematode in Tomato

6. Causal organisms
 Nematodes: Meloidogyne spp.
 Root knot nematodes (Meloidogyne spp.) are small, eel-like
worms.
 which overwinter in the roots of perennial weeds or as eggs
and larvae in soil or infected root debris.
 Larvae penetrate the roots and excrete a substance that induces
the formation of root galls.

7. ….Cont
 Injury to the roots affects the uptake of water and minerals and
eventually results in the development of above-ground
symptoms described previously.
 Infection by the root knot nematode also may "break" disease
resistance to Fusarium and Verticillium wilt.
 Root Lesions:
 Pratylenchus nematodes infect the root systems of tomato.
 They cause tears, or lesions, in the roots of the tomato plants
that they infect, causing damage to them and impairing
growth.
 The lesions caused by these nematodes have turned brown

8. Pratylenchus

9. Fusarium wilt in Tomato

10. Control
 Root knot may be prevented by avoiding the introduction of
the pathogen into the garden or field.
 Carefully check and discard any transplants showing swelling
or galling of the roots.
 Never introduce soil into the garden from areas where root
knot is known to be a problem.
 Rotation periods of 3 to 5 years with corn or other non-host
plants will reduce nematode populations in the soil.

11. ….Cont
 Root knot nematode populations in the soil may also be
reduced by a process called soil solarization.
 Solarization is usually done in mid-summer to maximize soil
heating effects.
 It is the heating process that kills eggs of the nematode.
 Prepare the soil by tilling and irrigating, then cover the soil
with a clear plastic film.
 The film should be left on the soil for at least 2 weeks to
ensure sufficient heating.

12. ….Cont
 African Marigolds, Tomatoes and Nematodes:
 Planting African marigolds two weeks before planting
tomatoes has been shown to reduce root lesion nematode
damage by 99 percent.
 This is because these flowers produce polythienyls, which are
chemicals that suppress root lesion nematodes, as well as other
species.
 Soil Additives
 Farmers in India have used products of the neem tree as
natural pesticides for hundreds of years. Soil that is just 1
percent "neem cake" showed a 67 to 90 percent reduction in
the number of both root knot nematodes and root lesion
nematodes.

13.  Disease resistance or tolerance of tomato varieties to
Verticillium Wilt (V), the common race of the Fusarium
wilt fungus (F), and the root knot nematode (N).
Early-season
• Pik Red (V, F, N)
• Set Star (V, F)
• Mountain Delight
(V, F)
Mid-season
• Celebrity (V, F, N)
• Sunny (V, F)
• Baja (V, F, N)
• Betterboy (V, F, N)
• Show me (V, F)
Late-season
• Burpee's (V, F)
• Beefmaster
(V, F, N)

14. Nematode on brinjal

15. Introduction:
 The root-knot nematode, Meloidogyne spp. and reniform
nematode Rotylenchulus reniformis are the major nematode
pests, causing serious damage to brinjal.
 These nematodes weaken the growth and vigour of the plants
and pre-dispose the roots to invasion by many root-rot and wilt
causing fungi and bacteria compounding the damage.
 The host range of these nematodes is very extensive, including
most vegetables belonging to many families.

16. Root-Knot Nematode
 The second stage juvenile of the root-knot nematode
penetrates the growing root tip and fixes a feeding site in the
cortex, as a sedentary endo-parasite.
 The nematode matures in 20-25 days and lays about 200-300
eggs in a gelatinous matrix on the infested root.

17. Root knot nematode in Brinjal

18. Symptoms of root knot nematode
 The plants show unthrifty development and stunted growth if
the infection has been severe.
 The leaves are yellowish green to yellow, tend to drooping and
then there is sudden wilting if wilt organisms are present.
 Sometimes, there is scorching of the leaf from the margin
inward.
 These symptoms, however, overlap with symptoms of many
other diseases.

19. ….Cont
 The most characteristic symptom of the disease is the
formation of knots or galls on the root system.
 The main root and the laterals bear spherical to elongated galls
which vary in size from very small to very large.
 In advanced stages the galled tissues decay and are invaded by
other pathogenic and saprophytic organisms.

20. Reniform Nematode
 The reniform nematode penetrates the secondary and tertiary
roots and causes necrotic lesions.
 The female is attached to the root as a semi-endoparasite with
its posterior kidney shaped body protruded outside the root.
 An adult female lays 50-75 eggs in gelatinous matrix.

22. Symptoms of Reniform nematode
 The infected plants shows multitude of symptoms viz., stunting, leaf
curling and chlorosis, inhibition of root development, root
discolouration and necrosis, cortical necrosis, premature dropping of
flowers, malformation of fruits and seeds.
 Apart from this direct damage, injuries caused to the roots due to
penetration by the nematodes facilitate easy entry to soil-borne
fungal pathogens viz., Phytophthora and Fusarium, causing root rot
and wilt diseases.

23. Factors responsible for nematode
disease in brinjal
 Excessive soil moisture coupled with lack of aeration favours
the nematode development.
 Sandy and light soils favours their movement best.
 Generally, temperatures of 25 to 28o C are best for infection,
rapid multiplication of root-knot nematodes.

24. Management
 Summer ploughing and exposing the soil to sunlight for one or two
months during April-May prior to planting helps to reduce the
nematode and pathogen load in the soil.
 Provision of good drainage and avoidance of water stagnation.
 Use healthy seedlings for planting.
 Crop rotation with non solanaceous crops such as paddy, gingelly,
pulses, groundnut helps in reducing the build up of nematodes in
soil.

25. ….Cont
 Rotating brinjal with marigold helps to reduce the nematode
incidence for the next crop.
 Application of neem cake @ 750-1000 kg per hectare or saw dust @
2 tonnes per hectare gives good control.
 Nursery soil may also applied with nematode antogonist and plant
health promoting bacteria, Pseudomonas fluorescens @ 1 kg/metre2
cent at the time of seed sowing to further ensure nematode
elimination.

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