3. INTRODUCTION OF NEMATODE
Nematodes are omnipresent
Transmitted through variety of methods.
Irrigation water is the prime source infected
Control methods is needed to raise crops
5. Regulatory Method:
Quarantine / exclusion :
This implies exclude the entry of a pest .
Buy or grow transplants that are
Use nematode-free soil or potting medium.
Clean tools and equipment when changing areas
Remove infected plant roots .
7. Cultural Control:
Crop Rotation :
keeping nematode population under check especially when
there are distinct host preferences.
Susceptible crops should be grown once in few years
Rotating them with non-host crops.
Vegetables should not be grown in same field repeatedly.
Keep weeds in check.
8. Fallowing and Ploughing :
Keeping the land fallow and deep ploughing reduce
nematodes e.g. root knots and others.
Nematodes are sensitive to heat and drying action of the sun
and the wind.
So in hot and dry condition fallowing and ploughing are best
remedy of nematodes control.
10. Use of Organic Amendments:
Green manure compost, oil-cakes has been found to
These encourage the growth of natural enemies and
Raising green crops also enhance development of some
predacious nematodes in soil.
11. Use of Resistant and Tolerant Varieties:
The most practical and economical methods of controlling
Multi-resistant strains of plants to nematodes has been made
The main drawback sometimes is the development of
resistant breaking nematodes which makes the process futile.
Resistance has been mainly to root-knot nematode.
Resistant and non resistant roots:
12. Flooding :
Flooding can be adopted where there is an enormous
availability of water.
Under submerged conditions, anaerobic condition, kills the
nematodes by asphyxiation.
Chemicals lethal to nematodes such as hydrogen sulphide
and ammonia are released in flooded condition which kills
13. Adjust planting time:
Nematode life cycle depends on the climatic factors.
Adjusting the time of planting helps to avoid nematode damage.
In some cases crops may be planed in winter when soil
temperature is low ad at that time the nematodes cannot be
active at low temperature.
Early potatoes and sugar beets grow in soil during cold season
and escapes cyst nematode damage.
14. Antagonistic crops:
Certain crops like mustard, marigold and neem have chemicals
or alkaloids as root exudates which repel or suppress the plant
In marigold plants : α terthinyl and bithinyl compounds
In mustard : allyl isothiocyanate
Pangola grass: Pryrocaterchol
Such enemy plants can be grown along with main crop or
included in crop rotation.
15. Trap cropping :
Two crops are grown in the field, out of which one crops is highly
susceptible to the nematode.
The nematode attacks the susceptible crop.
By careful planning, the susceptible crop grown first and then
removed and burnt.
Thus the main crop escapes from the nematode damage.
Cowpea is highly susceptible crop can be grown first and then
removed and burnt. Cowpea is highly susceptible to root knot
nematode and the crop can be destroyed before the nematodes
Heat treatment of soil :
This is a general practice for soil sterilization against all
organisms harmful or beneficial.
Nurseries use autoclaved soil [ 30 psi for 30 minutes] for
In greenhouses steam is released through perforated pipes
running through the soil.
Dry heating of soil by burning off the standing crop waste is
17. Hot water treatment of planting material :
It is mainly used for transplanted crops, bulbs, rhizomes, root
stock and tubers.
Usually dormant bulbs of ornamental plants and root stocks of
citrus are given this treatment.
Hot water treatment of rice seed is a very effective method to
control white tip nematode which is transmitted through seed.
18. Solarization :
This method involves covering moist soil with polythene film
during period of intense sunlight and heat.
This capture energy from sun thus bringing change in
physical ,biological and chemical changes in soil.
The soil temperature increased is lethal to many of soil borne
It increase soil fertility by increasing availability of nitrogen
and other essential nutrients.
This method of nematode management is very useful where
heat from sun rays is sufficient.
It only reduce nematode population , but not enough to finish
19. Dry heat:
Dry heat also reduce nematodes population.
Nematodes egg and their juvenile stages are usually killed if
they are exposed to dry heat.
Use of oils :
Spraying 15% water soluble oil reduces infestation by
Many of oils also used also reduce the counts of eco-parasitic
By this spraying nematodes movement sis restricted and
quantity becomes low
20. Exposure to direct sunlight:
Spread infested layer of soil in thin layers up to few cm on soil.
Exposed layer to sunlight for 10 days in summer to eliminate
nematodes that are present in soil layer .
This practice is useful for preparing soil mixtures for
ornamentals and nursery beds.
It is an effective means to kill nematodes though it is non-
feasible and non-practical.
UV rays used are lethal to nematodes.
Many other radioactive rays are used in this management
21. Osmotic pressure :
Addition of dextrose or sucrose to nematode infested soil is
detrimental to nematodes.
This reduce or restrict nematodes production or population.
Although this method is non-economical and non-practical.
Floatation of seed :
This is done in order for removal of nematode galls from seed
material and floatation.
Flooding and floating of seeds are done to control nematodes
Seed also cleaned by mechanical cleaners to kill gall
23. Chemical control
These are first to identify as control in plant parasitic
They may be applied to the soils as liquids, emulsions or
granules but the active ingredient spreads in the soil in the form
of a gas.
These are applied as pre-plant treatments mostly.
It is essential that the soil be treated is well prepared to a seed
Soil moisture is moderate , uniform and the soil temperatures
should between 15 to 30oC at the time of application.
DD and EBD are highly phytotoxic and are applied 3 to 4
weeks before planting.
DBCP can however can be used with irrigation water around
the roots of plants as recommended.
DBCP mostly used as pre –planting .
It is mostly used on perennials (citrus root nematode).
These are applied to living plants parts and as pre –plant
treatments to annual crop.
These are applied in granular form.
These are applied during or shortly after planting to wet soils.
It is important to have their application along irrigation water in
order to have proper dispersal through out soil surface.
Some of nematocidal are insecticidal thus providing early insect
These are classified as carbamates and organo-phosphates.
These compounds control many soil and foliar feeding
27. non fumigants fumigants
Applied during planting
and post planting
Effective at lower
Control both soil and
Less residual activity
Not effective at lower
Control only soil
28. Nematicides : Used against :
Dichlorofenthion First used for management of root knot
nematode on turf and ornamentals.
Thionozin Used against as sting nematodes in
maize and root knot in vegetables.
parathion Used against A.fragarie (1948)
Dazomet Used against root knot and lesion
phorate Used against many nematodes as
stunt, root lesion etc.
fensulphothion Used against turf nematodes
phenamiphos Used against root knot and bare root
dip in citrus.
Commonly used nematodes :
29. Nematicides Used against :
Ethoprop Used against root knot nematodes
affecting tobacco ,tomato and also
Aldicrab Used against tobacco cyst nematode
carbofuran Used against many nematodes as
oxyamyl Used against many nematodes.
30. Experimental compounds :
Some compounds also posses nematicidal activity for
They are :
32. Characteristics :
Parasitism is always lethal
Easily manipulated in laboratory
Can be mass produced Easily disseminated with
Potential for establishment & recycling
Provides control for extended period
Not harmful to environment
Shelf-life of at least one year
Compatibility with others
33. Predators of nematodes:
Important predators of plant parasitic
nematodes are mites , insects ,enchytrieds
and migratory nematodes.
34. Parasite of nematodes:
Bacteria and some fungi are major parasites
of plant parasitic nematodes.
Several fungi are isolated that parasitizes the
Fungi act as opportunistic .
No virus still documented to harm nematodes.
35. Use of nematophagus fungi
It is parasite .
These forms trap usually.
Several species of soil-dwelling fungi produce traps to
ensnare nematodes before they infect them.
Traps come in many forms: adhesive hyphae,
networks, knobs, rings, and constricting rings.
Some trapping fungi can proliferate in soil in the
absence of nematodes while others are more
dependent on nematodes as a nutrient source for
As Arthrobotrys oligospora parasitic fungi
36. ENDOPARASITic ENDOZOIC
These fungi produce either simple or flagellate adhesive spores
which upon contacting a nematode quickly and firmly attached to
It then germinates and enter the nematode body through germ
Simple spore are ingested by nematode, reach the esophagus /
buccal cavity where they germinate e.g.. Harposporium
While sticky spores stick to the nematode body & germinate and
penetrate directly through the nematode cuticle, produce
infective hyphae e.g. Meria coniospora & Nematoctonus bisporus
Nematodes get restricted nutrients and ultimately weakens.
37. Parasitic fungus (zoosporic)
Zoospores are motile spores that are propelled by
one or two flagella.
When zoospores locate a host, they attach to the
nematode cuticle, often near a body opening
(mouth, anus, vulva), shed their flagellum, and
become sedentary (i.e., encyst).
The encysted zoospores infect the nematode
cuticle by forming a penetration tube that enters
through an orifice or directly penetrates the
When the resources within the infected nematode are
exhausted, the hyphae differentiate to form sporangia.
Zoospores are produced within the sporangia and enter
the soil via an exit or discharge tube which is formed
when the spores are mature.
Zoospore-forming fungi are believed to be
opportunistic parasites of vermiform nematodes,
attacking or colonizing weakened or dead nematodes.
As Catenaria anguillulae
39. Egg parasitic fungus :
There are a large number of fungi that can
parasitize nematode eggs, and the sedentary
juveniles and females of cyst and root-knot
These fungi categorized in two groups.
One is obligate parasitic fungi those that can grow
only in nematodes.
Second is facultative parasitic fungi that can grow
to some extent in nematodes as well as on
organic matter in the soil.
40. Toxic chemicals released:
The filamentous fungi have been widely studied for
their effectiveness in controlling nematodes.
The mechanisms involved in this is direct through
antibiosis and parasitism.
Trichoderma grows around the target and releases
toxic compounds and different lytic enzymes mainly
chitinases , glucanases and proteases.
These proteins facilitate Trichoderma penetration into
the nematode and the utilization of the nematode
components for nutrition.
The role of these lytic enzymes has been proved in
Some of them are endospore-forming actinomycetes that
are parasites of nematodes.
Some rhizosphere-inhabiting bacteria are antagonistic to
Some bacteria inhibit nematode egg hatch and/or
penetration of roots.
Mechanism involved Production of antibiotics that kill
Degradation of the root exudates that the nematode relies
on for host location and to stimulate egg hatch.
42. Mites :
The soil mite Lasioseius subteraneus
Mesostigmata Ascidae are an aggressive
predator of nematodes that colonizes
greenhouse cultures of root-knot nematodes.
This mite has a generation time of less than 1
week at 28 ºC and can lay up to 18 eggs per
day when feeding on nematodes and kill them
1.Like cyst nematode of potatoes of wheat and potato…. 3) but should be rotated with cereals in order to reduce infestation with root knot nematodes. . However, economics of growing ‘rotation’ crops, practicality including land requirements, and specific nematode host range many times limits rotation options. This practice should always be keep in mind, even in small garden plots, where perhaps sweet corn could be rotated with more susceptible crops such as okra.
1)Two to three times plouging at intervals of 10-15 days.
1) of neem, mahua, mustard, groundnut, cotton, linseed and karanj] sawdust …2) These cakes incorporated at the rate of 1 to 1.5 tons/ ha has been found to give good control of root knot nematodes and should be practiced
1) . Resistance to root-knot nematodes is available in crops such tomato, soybean, snap bean, southern peas and several other crops.2) Though lot of work has been done on developing varieties of tobacco, cotton, soybean, cowpea, capsicum, tomato, sweet potato much more needs to be done. 3 ) A word of caution, do not rely solely on plant resistance since certain populations of nematodes can overcome resistance beginning either immediately or sometimes several years after regularly planting the resistant plant..4) Little resistance is available to other nematode species…
Asphyxiation : Lack of oxygen for the survival of nematode.
since the nematodes are not that much active, to cause damage to the crop during cold season.
In marigold (Tagetes spp.) plants α terthinyl and bithinyl compounds are present throughout the plant from root to shoot tips.
1....... Temperatures go up to 82 o C for 30minutes
1) Effective time and temperatures vary with respect to the plant parts [ 10 to 60 minutes at 43 to 54 oC ]. /… 2) rice seed treated at 52 to 55oC for 10 to 15 minutes is a very effective method to control white tip nematode which is transmitted through seed.
……….. Effective time and temperatures vary with respect to the plant parts [ 10 to 60 minutes at 43 to 54 oC
Obligate Parasites - Nematophthora gynophila and Catenaria auxiliaris
Zoospores of both fungi encyst on the cuticles of young female cyst nematodes, penetrate, and consume the internal contents, including the eggs. Within the nematode body, zoospores develop within sporangia and are released through exit tubes into the soil. Both N. gynophila and C. auxiliaris form resting spores which are more persistant than the fragile zoospores.
Facultative Parasites- Many fungi found within cysts and within egg masses of cyst and root-knot nematodes are common soil saprophytes and are only weak parasites of nematodes. However, some isolates of these fungi are aggressive nematode parasites.
Examples of fungi that have been identified as aggressive parasites of sedentary stages of cyst or root-knot nematodes. Not all isolates of these fungi are aggressive parasites.
Cylindrocarpon destructans, Dactylella oviparasitica , Paecilomyces lilacinus , Verticillium chlamydosporium , Verticillium lamellicola, Verticillium lecanii , Verticillium leptobactrum , Verticillium suchlasporium
Streptomyces avermitilus : The toxin avermectin is produced by the actinomycete Streptomyces avermitilus in fermentation. It is active against insects at very low dosages, and formulations containing avermectin are utilized against insects and nematode parasites of animals and on a number of crops. Although activity has been shown against plant parasitic nematodes, it has never been commercially developed for this purpose………..