PowerPoint Presentation
Chemical control of nematodes
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The demandThe elimination of nematodes from some crops is
essential for certain export requirements, particularly of
high-value horticultural products. Chemical treatment with
fumigants or nematicides may be the only technique available, and
from the plant quarantine standpoint it is important that their use
is retained.EfficacyFumigants.Several general purpose fumigants
give excellent control of nematodes in soil. The efficacy is
related to their high volatility at ambient temperatures. All
fumigants have low molecular weights and occur as gases or liquids.
As they volatilize, the gas diffuses through the spaces between
soil particles; nematodes living in these spaces are killed.
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Plant-parasitic nematodes are at their most vulnerable during
their active phase in soil when searching for the roots of host
plants. Once endoparasitic species have penetrated a root, control
with chemicals is more difficult as nematicidal compounds have to
be non-phytotoxic and preferably systemic.
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Important Considerations:costs and economics; use restricted
primarily to higher value crops in cash economy.phytotoxicity; may
only be available for preplant use.lack of specificity; disruption
of the soil food web, including antagonists, competitors and
beneficials.residue problems; soil, groundwater, food - Prop 65 and
other legislation.non-visible target; volumes of soil are treated
rather than foci of infestation; saturation rather than precision
application.movement and persistence; chemical may have to permeate
the soil from the site of application in order to contact target
nematodes, and be sufficiently persistent to achieve lethal
concentrations at each site.
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Important Considerations:dissipation; after lethal dose has been
delivered, chemical should break down or otherwise dissipate in the
environment to allow plant growth and soil food web recovery.
amounts and technologyfor application; volume of soil to be
treated requires transportation, handling and application of large
volumes of toxic materials. Older equipment introduced fumigants to
appropriate soil depths but was not well-engineered for ensuring
transfer to and from the delivery tank without escape to the
atmosphere or human exposure.
human toxicity; health hazards and risks associated with
volatility, manufacture, handling, application and accidents;
materials may have high mammalian toxicity and/or be suspected
carcinogens..
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There are two main categories of chemical nematicides based on
their volatility - non-fumigants and fumigants.
Fumigant nematicides disperse through the soil as a result of
their volatility.
Non-fumigant nematicides must be mechanically mixed throughout
the soil profile, or spread in aqueous solutionNematicide
grouping
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Two main groups of chemicals, carbamates and organophosphates,
and some alternative materials.
1. Carbamates: Oall have O-C-NH-CH3 groupapplied to soil in
water or incorporated
Examples: 1.1. Temik (aldicarb), manufacturer: Rhone-Poulenc,
1965
contact and systemic nematicide, insecticide, acaricidegranular
formulation Category I pesticideunder EPA review - groundwater
contaminationNon-fumigant Nematicides
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Non-fumigant Nematicides1.2. Furadan(carbofuran)
Manufacturer: Mobay, Introduced: 1969contact and systemic
nematicide, insecticidegranular and liquid formulations Category I
pesticideunder EPA review - bird toxicityEPA Administrative Review,
August 2006.1.3. Vydate(oxamyl)
Manufacturer: Dupont; Introduced: 1972contact and systemic
nematicide, insecticidealso considered to have systemic
actionliquid formulation Category I pesticide
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Non-fumigant Nematicides1.4. Standak(aldoxycarb)
Manufacturer: BASF;Introduced: 1976contact and systemic
nematicide, insecticideliquid formulation? Category I pesticide
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2. Organophosphates:
all contain P and S groupsapplied to soil in water or
incorporated. 2.1. Dasanit (fensulfothion) Manufacturer: Bayer;
Introduced: 1957contact nematicide, insecticidegranular and liquid
formulations Category I pesticideNon-fumigant Nematicides
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2.2. Mocap (ethoprop)
Manufacturer: Bayer; Introduced: 1963contact nematicide,
insecticidegranular and liquid formulations Category II
pesticide
Non-fumigant Nematicides
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2.3. Nemacur (phenamiphos, fenamiphos)
Manufacturer: Bayer; Introduced: 1969. contact and systemic
nematicide, insecticidegranular (10G and 15G) and liquid (Nemacur
3) formulations. The Nemacur 3 formulation is used in tree and vine
plantings in California. Withdraw the registration of Nemacur in
the USA effective May 31, 2007.Category I pesticideActive
ingredient (35%): Ethyl
3-methyl-4-(methylthio)phenyl-(1-methylethyl)phosphoramidatePhenamiphos
is reported to become less effective when applied repeatedly to
soils, possibly due to selection for organisms that degrade it more
rapidly (Davis, et al., 1993; Johnson, 1998).Non-fumigant
Nematicides
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3. Other Modes of Action:
3.1. ClandoSan (chitin+urea) Manufacturer: I-gene, 1985?enhances
chitinolytic fungigranular formulation natural nematicide made from
crab and crawfish exoskeletons The product acts in soils as a
biological control agent by stimulating the growth of normal soil
microorganisms, which produce chitinase, and other enzymes that
degrade chitin present in the cuticles and eggs of plant-pathogenic
nematodes. ClandoSan(R) does not have a direct adverse effect on
plant-pathogenic nematodes either in vitro or in sterilized or
irradiated soils and only acts indirectly to suppress nematode
populations in soils.Non-fumigant Nematicides
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3.2. DiTera (fungal metabolite)
Manufacturer: Abbott Labs. Now by Valent Biosciences;
1996;Antibiotic from Myrothecium verrucaria.DiTera ES is a liquid
formulation.DiTera G and DiTera WDG are granular formulations.Good
mammalian and non-target toxicity characteristics.DiTera WDG is
listed by the Organic Materials Review Institute (OMRI) for use in
organic productionRecommendations for DiTera use in
vineyardsNon-fumigant Nematicides
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3.3. Nema-Q
MontereyAg ResourcesMain ingredients are saponins from Quillaja
saponaria trees (Soapbark), native to Chile.OMRI Listed for organic
production.Liquid extracts of tree biomass are refined to remove
colloids then heat concentrated.Rich in saponins, polyphenols,
sugars and salts.Non-fumigant Nematicides
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Non-fumigant Nematicides3.4. Movento
Manufacturer: Bayer CropScience, 2008.Lipid biosynthesis
inhibitor based on the Tetramic acidsMovento is described by the
manufacturer as "a revolutionary new insecticide with unique 2-way
systemicity, which distributes the active ingredient upwards and
downwards in the plant"Grapes, citrus, vegetables, tree fruits,
tree nuts, Christmas trees and hops.Exudes into the rhizosphere and
kills both plant- and microbial-feeding nematodes. To maximize leaf
uptake and systemicity, Movento must be mixed with a spray adjuvant
that provides spreading and penetrating properties.
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Non-fumigant Nematicides
3.5. DRAGONFIRE-CPP
DRAGONFIRE-CPP is a sesame oil derived from a wild cultivar of
Sesamum indicum (Botanical Nematicide, Fungicide, and
Insecticide).Containing aldehyde, ketones and linolenic
acidsNematodes are deterred from feeding on the plant once the
DRAGONFIRE-CPP has been absorbed by the plant roots. Ingestion by
the nematode produces death due to the drying effects of the
linoleic and lioleic acids. Contact with the CPP compounds causes
the nematodes to become lethargic and affects the reproduction
cycle. Long-term effects are a reduction of population and an
opportunity for plant recovery and growth.
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Non-fumigant Nematicides3.6. Furfural
2-furfuraldehyde, a derivative of pentose sugarsFurfural is
formed from pentosan, a five-carbon cellulose which occurs in
corncobs, bagasse, wood chips and other organic material. The
organic source is heated to 100C, the pentosan is hydrolysed to the
soluble sugar pentose (xylose) and dissolves in the available
waterToxicity: LD50 (oral) for a mouse: 400 mg/kgLD50 (oral) for a
rat: 127 mg/kgLD50 (oral) for a guinea pig: 541 mg/kg
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