Nematicides

1. UNIVERSITY OF AGRICULTURAL SCIENCES, BENGALURU
COLLEGE OF AGRICULTURE, VC FARM, MANDYA.
“NEMATICIDES, USES AND
MODE OF ACTION”
Presented by
Maruthi H Patil
PAMM0019
MSc. (Agri.) 1

2. What is a nematicide?
• A nematicide is a type of chemical pesticide
used to kill plant-parasitic nematodes.
• Nematistat are chemical compounds that do
not kill nematicides directly, but effective by
paralysing the nematode that unable to cause
plant injury.

3. HISTORY

4. NEED FOR NEMATICIDE
• NEMATODE becoming a major pest in
agriculture.
• Losses due to nematode attack are crossing
billion year by year.
• Nematode cuticle is permeable to a wide
range of organic compounds.

5. Characteristics of ideal fungicide

6. TYPES OF NEMATICIDES:
I. Natural nematicides
II. Artificial nematicides
• Fumigants
• Carbamates
• Organophosphates

7. I. NATURAL NEMATICIDES
Garlic developed polysulfide product
Neem cakes
Root exudates of MARIGOLD
Nematophagous fungi - Paecilomyces

8. Neem cakes

9. Nematophagous fungi - Paecilomyces

10. ARTIFICIAL NEMATICIDES:
• These are artificially synthesised chemical
compounds that are highly toxic and in some
extinct even carcinogenic used for nematode
control in a field.
• They might be fumigants, carbamates or
organophosphates.

11. CLASSIFICATION

12. FUMIGANTS:
 D-D
• This mixture of 1,2-dichloropropane and 1,3-
dichloropropene
• problems with groundwater contamination
resulted in its withdrawal from use in 1984.
• The 1,2-dichloropropane component was
relatively inactive as a nematicide at
concentrations used in agricultural fields.

13.  1,3-Dichloropropene:
• Substitute to 1,2dichloropropane.
• Eliminates ground water contamination.
• Combine activity over nematodes insects and
fungi.
• INACTIVE over Globodera rostochiensis

14.  Ethylene Dibromide:
• Abundantly used, but prohibited in USA in
1983 because of ground water contamination.
• Also it is a carcinogen.
• It was available in liquid formulations

15.  1,2 – dibromo – chloropropane:
• Once popular for specific nematode activity.
• used in postplant applications
• Banned in 1977 in US because 1/3rd of male
workers at DBCP manufacturing plant became
sterile.

16. Methyl Bromide
• Methyl bromide is a broad-spectrum fumigant toxic to nematodes.
• In 1997, methyl bromide was the fourth most commonly used
pesticide in the United States .
• It is agronomically useful against soil fungi, nematodes, insects, and
weeds.
• The Montreal Protocol, an international treaty regulating the use of
ozone-depleting substances, mandates the elimination of methyl
bromide use in developed countries by 2005.
• Methyl bromide is used as a gas; because of its lack of odor, small
amounts of chloropicrin are often added as an indicator of exposure
to applicators.
• Methyl bromide is the fastest moving fumigant in soils, followed by
chloropicrin, 1,3-D, EDB, methyl isothiocyanate, and DBCP.

17.  Chloropicrin
• One of the oldest soil fumigants,
• chloropicrin’s primary agricultural use in soils
is as a fungicide, although it does have
herbicidal and nematicidal activity.
• It is often added to 1,3-D formulations in
order to increase their fungicidal activity.
• The compound is acutely toxic and is used in
liquid formulations.

18.  Metam Sodium, Dazomet, and Methyl
Isothiocyanate (MITC)
• Metam sodium is a soil fumigant used to
control nematodes, fungi, insects, and weeds.
• When applied to soils, metam sodium is
converted to MITC, which is the active biocidal
agent.
• Dazomet is one of the few compounds with
activity as a fumigant that is supplied as a
granular formulation.
• Several brassicaceous plants contain
nematicidal isothiocyanates that release

19.  Sodium Tetrathiocarbonate
• Sodium tetrathiocarbonate is more recently
registered preplant soil fumigant active
against fungi, insects, and nematodes.
• It is supplied as a liquid formulation and may
be applied via drip or surface irrigation.
• Sodium tetrathiocarbonate rapidly degrades
in soil into carbon disulfide, sodium hydroxide,
hydrogen sulfide, and sulfur.
• Carbon disulfide is the active principle.
• Unlike other commonly used fumigants,
sodium tetrathiocarbonate does not readily
move through soil air and requires a high level

20. MODE OF ACTION
• Nematicide mode of action refers to the lethal
action of a nematicide on specific and vital life
processes within tissues of the nematode.
• For example, broad spectrum fumigant
nematicides penetrate the body wall of the
nematode directly and do not have to be
eaten to be effective. Once inside the body
cavity of the nematode, they affect different
internal organs when these organs are bathed
by body fluids containing the nematicide.

21. • Metam sodium (Vapam) is a very soluble
compound that becomes activated in water.
Decomposition is rapid in water. A secondary
byproduct (MITC) that forms in the presence
of water directly penetrates the nematode
body wall and simultaneously interferes with
many different vital processes, including
enzymatic, nervous, and respiratory systems.
• Death of the nematode is rapid under these
conditions. In general, fumigant
concentrations in internal body fluid
frequently reach equilibrium with soil
concentrations within about 30 minutes to 4

22. CARBAMATES
 Aldoxycarb:
Aldicarb is oxidized in soils to aldicarb sulfone’
insecticide/ nematicide aldoxycarb.
A flowable formulation is available.
 Carbofuran:
 A systemic insecticidal/nematicidal
carbamate in granular and liquid formulations.
 Probihibited because of kill the birds.

23. Oxamyl
• A systemic insecticidal/nematicidal carbamate
in granular and liquid formulations.
• Granular formation prohibited.
• Oxamyl is the only nematicide with
downward-moving systemic activity and thus
has registered foliar nematicidal applications.
• Said to control Pratylenchus penetrans on lily.
• Oxamyl is widely used throughout the world
and is less persistent in soil than is aldicarb

24. MODE OF ACTION
• The toxic properties of systemic nematicides
(Vydate) appear to be primarily protective
rather than directly toxic to the nematode.
• Systemic nematicides that are absorbed and
translocated into roots appear to only inhibit
feeding, temporarily inactivate nematodes, or
repel them from roots and surrounding areas,
rather than kill them, as the term
"nematicide" would indicate.
• In these cases, death occurs as a result of

25. Organophosphates:
 Ethoprop
Introduced in the 1960s
ethoprop is a nonsystemic nematicide.
The mobility of ethoprop in soil and its half-
life are strongly dependent on soil organic
matter
available as granules or emulsifiable
concentrates
non carcinogenic

26.  Fenamiphos
introduced in the 1960s,
It is widely used as a nematicide.
Like ethoprop, it is strongly adsorbed onto
organic matter.
It is acutely toxic but not shown to be a
carcinogen.

27.  Cadusafos:
This nonsystemic organophosphate used to
control nematodes and soil insects on
bananas and other crops
 excellent control of the burrowing nematode,
Radopholus similis.
possesses reduced risk for contaminating
groundwater
 Good control of the citrus nematode,
Tylenchulus semipenetrans
commercially available in granular and
microencapsulated formulations.

28.  Fosthiazate
 Recently developed in 1992.
 systemic organophosphorus nematicide with broad-
spectrum activity .
 A clay-based microgranule formulation is
available.
 control the lesion nematode Pratylenchus
penetrans on potato and root knot nematodes
(Meloidogyne spp.) on tobacco (26) and M.
arenaria on peanut ,
 But it failed to control M. javanica on tobacco
and Rotylenchulus reniformis on pineapple as well as
fumigation with 1,3-D ..

29. MODE OF ACTION
• Nonfumigants also penetrate the body wall of
nematodes directly. Unlike the fumigants,
these chemicals give little or no control of
fungal or bacterial diseases but can be
insecticidal depending upon the nematicide
used.
• As insecticides, the organophosphates
(Mocap) and carbamates (Vydate) act as
acetyl cholinesterase inhibitors, interfering
with normal nerve impulse transmission

30. • This is known to cause abnormal behavior,
paralysis, and death.
• However, these compounds are not as toxic to
nematodes as they are to insects and are not
generally considered to be true nematicides.
• Nematode mortality is often due to a
"narcotic" effect and behavioral modification
rather than killing. Disruption of nerve
impulses, which ultimately may be lethal at
high concentrations over an extended time
period, affects primarily nematode behavior
and development in soil.

31. For example,
• Body movement, mating behavior, and
mobility in soil are reduced, as well as root
penetration and feeding.
• Delayed egg hatch and molting and reduced
development within plant tissues may also
occur.
• Reduced nematode infection, development,
and reproduction in the plant are primarily
responsible for observed reductions in
nematode population growth following
nonfumigant nematicide treatment.

32. New emerged nematicides
(1)NIMITZ™ Nematicide Approved by EPA
(2)MCW-2, a new nematicide of the
fluoroalkenyl group, against the root-knot
nematode Meloidogyne javanica.

33.  NIMITZ™
 ADAMA USA.(Agricultural Solutions Ltd,.)
Revolutionizing global nematode control.
 The nematicide approved by EPA.
 “In contrast to fumigant nematicides, NIMITZ
simplifies nematode management by
lessening complex handling practices and
application restrictions” .

34. “it provides a non-restricted use pesticide
alternative that is effective, easy to apply, and
with lower environmental impact.”
Within one hour of contact, nematodes cease
feeding and quickly become paralyzed.
Within 24 to 48 hours, pest mortality occurs
rather than temporary nematostatic
(immobilizing) activity, as seen with
organophosphate and carbamate nematicides

35. • MCW-2
MCW-2, a new nematicide of the fluoroalkenyl
group, against the root-knot nematode
Meloidogyne javanica.
MCW-2 showed irreversible nematicidal
activity against second-stage juveniles of M.
javanica in vitro, following exposure for 48 h
at concentrations as low as 0.5 mg L-1 .

36. MCW-2 at 8 mg L(-1) inhibited nematode
hatching, which, however, recovered after
rinsing in water.
In pot and plot experiments, 0.5 mg MCW-2
L(-1) soil and 2 kg MCW-2 ha(-1), respectively,
controlled M. javanica similarly to or better
than fenamiphos or cadusafos at the same
concentrations.
It has a novel mode of action.

37. THANK YOU