beneficial role, entomopathogenic nematodes, root knot nematodes symptoms, host species

1. IMPORTANCE OF NEMATODES IN
HORTICULTURE CROPS AND
MAJOR CROPS AFFECTED BY ROOT
KNOT NEMATODE

2. • Nematodes are worm-shaped nearly microscopic
animals, many of which are virtually invisible to the
unaided eye
Of the known nematode species, approximately 50%,
25%, 15%, and 10% are free-living, marine, animal
parasites, and plant parasitic nematodes (ppns),
respectively.

3. BENEFICIAL ROLE OF NEMATODES
Role of nematode fauna
Regulating primary production
Predation
Energy transfer
Decomposition of organic matter
Nutrient cycling and
Pollution indicator in soil ecosystems
Weed control

4. ENTOMOPATHOGENIC NEMATODES
(EPN)
Steinernema, Heterorhabditis
symbiotic bacteria – Xenorhabdus,
Photorhabdus
Used in biological control of insects and
PPNs to certain extent
Availability of nematode based products
comparable with standard insecticides in the
world market

5. Entomopathogenic nematodes
The genera Steinernema and Heterorhabditis, is
extraordinarily lethal to many important soil insect pests and
yet safe for plants and animals; they are used to control
many soil inhabiting insects.

6. Free- living nematodes are very important in maintaining the
soil bio-dynamic system, especially in soil with low organic
matter content
It helps in microbial colonization of substrates and
mineralization of nutrients by disseminating microbial
propagules throughout soil.

7. Locust infected by
Mermithids
Larvae of black fly
infected by mermithids

8. Killed by Steinernema sp.

9. Killed by Heterorhabditis sp

10.  The common PPN species associated with crops are:
Root lesion (Pratylenchus spp.),
Bulb and stem (Ditylenchus spp.),
Foliar (Aphelenchoides spp.),
Dagger (Xiphinema spp.),
Root-knot (Meloidogyne spp.),
Lance (Hoplolaimus spp.),
Citrus (Tylenchulus spp.),
Spiral (Helicotylenchusspp.),
Ring (Criconemoides spp.),
Stunt (Tylenchulus spp.).

11. In addition, some ppns including species of
Longidorus (pin nematode),
Trichodorus, Paratrichodorus (stubby-root nematode)
and Xiphinema (dagger nematode) transmit plant viruses
which are difficult to manage.
These viruses and/ or the nematodes weaken the plants to the
point that they are more easily killed by other causes such as
disease, insect, cold, or other stress factors.

12. ROOT KNOT NEMATODE : Meloidogyne incognita

13. HOSTS: TOMATO, BRINJAL, CHILLIES,
BHENDI, SNAKE GOURD

14. SYMPTOMS
 Presence of galls on the roots (large fleshy galls in Snake gourd, large and firm galls in
other vegetable crops, very small galls in chillies).
 Plants wilt rapidly especially under dry growing conditions and are often stunted.
 Growth may be retarded and leaves may be chlorotic.
 In cases where seedlings infection has taken place, numerous plants die in the seed bed
and seedlings do not survive transplanting.
 In those plants that do survive, flowering and fruit production is strongly reduced.
 The losses caused by Meloidogyne on root and tuber crops like carrot both quantitative
and qualitatively, because nematode galling affects marketability.

15. RKN Juveniles penetrating into root

16. ROOT KNOT AFFECTED TOMATO PLANTS

17. Infected roots of watermelon

18. ROOT KNOT NEMATODE AFFECTED
CHILLI PLANTS AND ROOTS

19. Meloidogyne
– life cycle

20. Meloidogyne – life cycle

21. Giant Cells
Root galling

22. Identification
Meloidogyne….
incognita javanica
hapla arenaria

23. M. incognita
- sugarbeet
M. incognita
- cantaloupe
M. hapla
- lettuce
M. incognita
- soybean
(resistant – left
susceptible – right)
M. incognita
- cotton
Symptoms

24. Damage
M. chitwoodi - potato M. incognita
- sweetpotato
Meloidogyne sp.
- carrot

25.  MANAGEMENT
Only seedlings with roots free of galls should be selected
for transplanting.
Application of pseudomonas fluorescens @10g/m2 in
nursery.
Crop rotation with non-hosts or resistant crops.
Proper weed control
destruction of galled roots after harvest.
Soil solarization with clears plastic traps during summer.
Use of resistant cultivars.
Application of carbofuran 3G @ 1kga.I./Ha.

26. By
Maan
Thank you