describe - plant parasitic nematode , importance of PPNs ,biological control definition,mechanism , agents; nematophagous fungi, endophytic fungi, formulations etc.

1. BIOLOGICAL CONTROL OF
NEMATODES BY FUNGI
MASTER’S SEMINAR I
ON
PRESENTED BY
DURLAV HIRA
DEPARTMENT OF PLANT PATHOLOGY

2. INTRODUCTION
Plant-parasitic nematodes cause severe damage to world agriculture each year.
Nematicides, the chemicals which are used to control plant-parasitic nematodes, are
often toxic compounds causing both environmental and health problems (Nordmeyer
1992). Environmental and health concerns over the use of chemical pesticides have
increased the need for alternative measures in the control of plant-parasitic nematodes.
Several organisms are known to be antagonistic against plant parasitic nematodes.
Fungal biological control is an exciting and rapidly developing research area and there
is growing attention in the exploitation of fungi for the control of nematodes (K.-Q.
Zhang, K. D. Hyde, 2014).

3. WHAT ARE PLANT PARASITIC NEMATODES ?
Plant-parasitic nematodes are the major group, feeding and reproducing on living
plants and they are capable of active migration in the rhizosphere, on aerial plant
parts, and inside the plant. They can cause significant plant damage ranging from
negligible injury to total destruction of plant material. Although a few nematode
species feed on above ground plant parts, such as leaves, stems, flowers, and seeds,
most of these parasites feed on underground parts of plants, including roots, bulbs,
and tubers

4. Plant parasitic nematodes- Importance :
 PPNs –leading biotics which causing yield losses in different crops
 Small about 0.5 to 3 mm unsegmented worms
 Can affect the crops in different ways
1. Altering normal root cell division
2. Modifying plant cells for nutrient transfer
3.Transmitting viruses and creating wounds
 Crop loss estimated about US $125 billion
 Current-dependent on the highly toxic
annually
nematicides
Biological control
• Harmful to the physical environment
• Reducing the soil flora and fauna
(British ecological society report, 2015)

5. BIOLOGICAL CONTROL- DEFINITION
“Biological control asthe useof living organismsor their
products to eliminate or reduce the damages or losses due to
pests” (IOBC,2014)
(or)
“Biological control may be defined as reduction of
nematode population that is accomplished through the action of
living organisms other than the nematode-resistant host plants,
which occurs naturally or through the manipulation of the
environmentortheintroductionofthe antagonists”
(Stirling,1991)

6. BIO CONTROL AGENTS FOR PPNs
(WaliaandBajaj, 2013)
1. Fungi
2. Bacteria
3. Predatorynematodes
4. Protozoa
5. Tardigrades
6. Turbellarians
7. PredatoryMites
8. Collembolans
Biologicalcontrol
Fungi
Bacteria
Mites
86%
10%
2%

7. MECHANISMS OF BIOLOGICAL CONTROL
4mechanismsofbiological control
Predation
Parasitism
Competition
Antibiosis
Toxiccompounds
Fungi- Paecilomyces lilacinus
http://users.ba.cnr.it/ciancio/nematoda.html
Specializedstructures–predacious
Fungi-Arthrobotrytis spp
parasitisation
Fungi-Pochonia chlamydosporia
Food/Space
Fungi- A. dactyloides

8. NEMATOPHAGOUS FUNGI
• Nematophagous fungi are those fungi with the capacity to capture, parasitise or
paralyse nematodes at all stages of their life cycles(Li et al. 2000).
• Nematophagous fungi refer to a diverse group of fungi which colonize and
parasitize nematodes for exploitation of nutritious substances. Some of them are
obligate parasites of nematodes, but the majority is facultative saprophytes
(Jansson H-B ,2008).

9. TYPES
2. Endoparasitic fungi
3. Egg/cyst parasitic fungi
4. Toxin producing fungi
1. Predacious fungi/capturing
2.
Examples:
1. Arthrobotrys species
Monacrosporium cionopagum
3. M. gephyropagum
4. Dactylella lobata
5. D. brochopaga
6. M. doedycoides
7. D. candida
8. D. leptospora
9. Drechmeria coniodiospora
10. Paecilomyces lilacinus
11. Trichoderma spp.
12. Hirsutella rhossoliensis
13. Haptoglossa dickii
14. Catenaria anguillulae
15. Verticillium chlamydosporium
16. Dactylella oviparasitica
(Pandit,2014)

10. 1. PREDACIOUSFUNGI/CAPTURINGFUNGI
• Some fungi are predators and feed on nematodes, either by attacking eggs or
juveniles and/or by forming special hyphal structures to prey on moving
nematodes(Stirling, 1991).
• Most commonly found structures are adhesive nets of Arthrobotrytis spp. with a
three-dimensional network. The fungal hyphae form rings which constrict upon
nematode passage then the hyphae penetrate through the cuticle and feed on
nematode (review in Hallmann et al., 2009).
• Adding A. dactyloides to soil at an early developmental plant stage provides
protection against M. incognita penetration for 10 weeks (Kumar and Singh,
2006); long enough to prevent major plant damage.

11. Mycelium Adhesivenetwork Attachingknob
NonC. ring Constrictingring Adhesivezoospores(Pandit,2014)
Mode of Action

12. 2. ENDOPARASITIC FUNGI
Penetration
Proliferate
Killings
New Propagules (spores)

13. Nematodebody
Fungalspore(conidia)
Appressorium
Germtube
Infectednematodebody
Multiplicationofthe hyphae
Underfavourable conditions
(Pandit,2014)

14. ENDOPARASITIC FUNGI - EXAMPLES
• Other biocontrol fungi are endoparasitic soil fungi of Hirsutella spp. the fungi
produce adhesive conidia that attach to nematode cuticle in a manner much
like Pasteuria penetrans, and also have special requirements to grow in vitro
(Stirling, 1991).
Figure Conidia of the
endoparasitic nematophagous
fungus Drechmeria
coniospora adhere to the sensory
organs at the anterior end of a
nematode and block nematode
attraction.

15. 3. EGG/CYSTPARASITIC FUNGI
• Fungi that parasitize on eggs and/or females are facultative parasites. The
most important and well studied pathogen of Meloidogyne spp. is Pochonia
chlamydosporia (= Verticillium chlamydosporium).
• The fungus wraps around the egg, penetrates the shell and destroys the
insides of the egg with a cocktail of proteases (reviewed in Hallmann et al.,
2009).

16. Figure Top figures show infection of nematode egg by
the egg parasite Pochonia sp. Germling of the fungus
forms an appressorium after contact with the egg
(left). An adhesive is formed and the fungus penetrates
the egg shell, grows inside the egg, and digests its
contents. Bottom figures illustrates capture and
of a nematode by the nematode-trapping fungus
Arthrobotrys sp (Nordbring-Hertz
1973).
A nematode is captured in the three-dimensional
network trap (left) (Nordbring-Hertz and Mattiasson
1979).
The middle figure (enlargement of left figure) shows the
trap, covered with adhesive, penetration of the
nematode cuticle, and formation of an infection bulb.
The trap and infection bulb contain dense bodies (dark
dots) (Bird and Bird 1991).
The right figure shows an enlargement of the middle
figure with the multi layered nematode cuticle covered
with a surface coat.

17. 4. TOXINPRODUCINGFUNGI
• The toxin-producing fungi secrete a toxin that immobilizes the nematodes
before penetration of hyphae through the nematode cuticle (Jansson H-B ,2008).
• Finding that basidiomycetous Pleurotus and Coprinus have some species (like P.
ostreatus and C. comatus) that produce toxin (Barron GL ,1984., Zhang K ,2004).
• Antibiotic (nematicidal and antifungal) activities have been demonstrated for
Drechmeria coniospora, Harposporium anguillulae, Lecanicillium, Paecilomyces
lilacinus, and Pochonia . Paecilomyces lilacinus secretes acetic acid that paralyzes
juvenile nematodes (Arpin N, Favrebonvin J ,1991).

18. ENDOPHYTIC FUNGI
• Some fungi grow within plant tissue but do not cause lesions or other disease
symptoms and are referred to as endophytes.
• Acremonium spp. may secrete general toxins that induce plant root
modifification which decrease nematode feeding and reproduction (Bernard EC,
Gwinn KD ,1991).
• A number of endophytic fungi are nonpathogenic isolates of ordinary plant
pathogens like Fusarium oxysporum that during in vitro tests secreted
metabolites which were toxic to Radopholus similis, Meloidogyne incognita and
Pratylenchus zeae (Hallmann J, Sikora RA ,1994).

19. MASS PRODUCTION OF FUNGI
• Liquid culturing of fungi for mass production of spores and mycelium has often been
considered best for biological control (Papavizas et al., 1984).
• Cornmeal and potato dextrose media have been advised for mass culturing of endoparasitic
fungi such as Drechmeria coniospora, Verticillium balanoides and Harposporium anguiulae
(Lohmann & Sikora, 1989).
• Recently Siddiqui and Mahmood (1994) suggested culture of P. lilacinus on leaf extracts and
leaf residues for nematode control.
• Endoparasitic fungi generally have poor growth outside the nematode host (Barron, 1977).
• Members of the Deuteromycetes, however, can be grown on artificial media, but attain only
minimal growth (Durschner, 1983).

20. FORMULATION
Granular formulation is generally considered to be most suitable for microorganisms
that are to be applied to soil. There has been considerable interest in encapsulating
biocontrol agents in gellants such as sodium alginate (Fravel et al., 1985). Kerry (1988)
showed that hyphae of V. chlamydosporium grew approximately 1 cm from alginate-
bran granules and suggested that a granular formulation may be suitable for this
species. Diatomaceous earth granules impregnated with 10% molasses, lignitestillage
granules and alginate-clay pellets have all proved suitable carriers for biocontrol
agents (Backman & Rodriguez-Kabana, 1975; Jones et al., 1984; Fravel et al., 1985).
Paecilomyces lilacinus formulated on alginate pellets or diatomaceous earth granules
showed promising results in nematode control (Cabanillas et al., 1989).

22. LIMITATIONS OFNEMATOPHAGOUSFUNGUS
 Highselectivityorhost specificity.
 Requirementofadditionalcontrol measures.
 Thecorrecttimeof application.
 Delayedeffector mortality.
 Storageproblem.
 Difficultyofculturinginlarge quantities.
 Shortresidual effectiveness.

23. CONCLUSION AND FUTURE PROSPECTS
Since the infestation by nematodes causes severe damages to the crop and huge yield losses
which also leds high application of hazardous chemical to the soil to avoid all such problemd .
Nematophagous fungi have proven to be best both economically and ecologically.
Nematophagous fungi are ubiquitous organisms with the capacity to attack, infect and digest
living nematodes at all stages, adults, juveniles and eggs. They may use trapping organs, spores
and appressoria to initiate infection of their nematode hosts. Out of the fungi tested as
biocontrol agents, P. lilacinus, V. chlamydosporium, D. coniospora, H. rhossiliensis and
Arthrobotrys spp. gave significant control in field and pot tests in various agroclimatic
conditions(LòpezLlorca et al. 2008). The ability to colonize plant roots by nematophagous fungi
is a novel area of research that deserves in-depth investigations.

24. BIBLIOGRAPHY
• Nansen P (1993). Current and future prospects for control of ostertagiasis in northern Europe—examples from
Denmark. Vet Parasitol 46:3 –21.
• Nordmeyer D (1992). The search for novel nematicidal compounds. In: Gommers FJ, Maas PWTh eds. Nematology
from Molecule to Ecosystem. Dundee: European Society of Nematologists. pp 281 –293.
• Stirling G.R. 1991. Biological control of plant-parasitic nematodes. Wallingford, UK, CAB International: 282.
• Li, T. F., Zhang, K. Q., & Liu, X. Z. (2000). Taxonomy of nematophagous fungi (Chinese). Beijing: Science Press.
• Tunlid A, Jansson H-B, and Nordbring-Hertz B (1992). Fungal attachment to nematodes. Mycol Res 96:401 –412.
• Hallman J., Davies K.G., Sikora R. 2009. Biological control using microbial pathogens, endophytes and antagonists.
In: Root-knot Nematodes. Perry R.N., Moens M., Starr J.L (eds.). Wallingford, UK, CAB International: 380-411
• Anderson MG, Jarman TB, Rickards RW (1995) Structures and absolute confifigurations of antibiotics of the
oligosporon group from the nematode-trapping fungus Arthrobotrys oligospora. J Antibiot 48:391–398

25. Thank You
Presented by
Durlav Hira
M.Sc.(Plant Pathology)