principles and practices of nematode control 5/30/2014 walia ccshau 1
TRANSCRIPT
Principles and Practices of Nematode Control
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TerminologyPi = Initial Nematode Population Pt = Threshold level (ETL, Damaging level,
Pathogenic level)Pf = Final Nematode Population
Nematode control required only if Pi > PtNematode Control - aims at eradicationNematode Management – aims at keeping the
nematode population below Pt
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A diagrammatic relationship between phytonematode populations and crop loss
Per
cent
age
yiel
d
Crop compensates any injury caused
Tolerance level of crop and plant Threshold of
nematode numbers above which yield loss becomes significant
Yield decreases as nematode numbers increase
Yield loss reaches maximum
100
75
50
25
Logarithmic scale of nematode numbers per plant
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Methods of Nematode Management
CulturalPhysicalChemicalHost resistanceRegulatoryBiologicalIntegrated
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Cultural MethodsCrop rotation
Growing a non-host crop in between two susceptible ones
Non-host crop must be economically viable, locally acceptable and should not promote any new pest of disease problem
Rotation of wheat with gram, mustard for the control of Heterodera avenae
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Crop Rotation
Wheat - Wheat Oats - Wheat
Wheat - Wheat Fenugreek - Wheat
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2. FALLOWING
KEEPING THE FIELD BLANK
• FallowingPPNs are obligate parasites, cannot survive without food
• FloodingPPNs are aerobic; they will die due to asphyxiation in flooded lands
Cultural Methods
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Cultural MethodsPropagation through healthy planting material
Many nematode diseases spread through infected planting material; burrowing nematode in banana suckers, citrus nematode in infected citrus saplings, earcockle disease of wheat with contaminated seed
Removal or destruction of infected plantsRemoval and destruction of root stubbles soon after
harvest
Organic manuring/AmendmentsDecomposition products (fatty acids) are toxic to PPNsIncrease in the population of micro-organisms,
including nematode antagonistsImproved plant growth leads to tolerance against
nematode damage
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Cultural MethodsTrap crops
Nematodes penetrate but fail to develop inside some crops like Crotalaria; can be used as green manure after a few days
Antagonistic cropsRoot exudates of certain crops contain nematoxic
compoundsOnionGarlicTagetes (ᾳ-terthienyl)Asparagus (asparagusic acid)
Can be used as interculture
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Cultural MethodsTime of sowing
Advancing crop sowing by 2-3 weeks to escape nematode infection; older crop suffer less damage even if infection occurs
Soil solarizationDeep summer ploughingPlastic mulching
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Physical methodsMost nematodes cannot tolerate
temperature > 50-60 CHot water treatment of infected plant
material (bulbs, corms, tubers, rhizomes runners, seeds etc. ) is highly successful
Temperature-Time combinations are to be standardized for each crop/material
ExamplesHWT of bulbs of ornamental crops against
Stem & Bulb nematode, Ditylenchus dipsaciWhite tip disease of rice against white tip
nematode, Aphelenchoides besseyi
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Chemical controlInvolves use of Nematicides or
NematocidesPre-requisites
When Pi is very highCrop is valuableQuick results are warranted
Generally discouraged because ofResidue problems in edible partsEnvironmental pollutionToxicity to non-target organismsResurgence of pest problemsCost considerations
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Classification of Nematicides
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FumigantsHighly volatile halogenated hydrocarbonsUpon application into soil, turn into gaseous
phase and diffuse through soil pore spacesKill nematodes due to blocking enzymes by
substitution with halogen moietiesUsed extensively during 1950-60sExamples
DD – Dichloropropane and dichloropropeneEDB – Ethylene dibromideMBr – Methyl bromide1,3 D – 1,3 dichloropropeneDBCP - Dibromochloropropene 04/10/23Walia CCSHAU14
Problems involved with FumigantsRequire high doses which are phytotoxic,
hence need pre-plant applicationWaiting period of 3-5 weeksNeed special applicatorsNeed soil surface sealing with coversNeed special field preparations Efficacy dependant upon edaphic factorsSome proved carcinogenic and leave residues in fruits
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Non-fumigants Advantages
Effective against insects alsoEffective at low dosagesEasy to apply and handleLess phytotoxic an can be applied to standing cropsMostly systemic in natureRelatively non-volatile
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OrganophosphatesCommon name Trade name
Organophosphates
Ethoprop Mocap
Fensulfothion Dasanit
Phenamiphos Nemacur
Phorate Thimet
Thonazin Nemaphos
Organocarbamates
Aldicarb Temik
Carbofuran Furadan
Metham Sodium Vapam
oxamyl Vydate
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Effect of Carbofuran against CCN in Wheat
Untreated Carbofuran
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Economising Nematicidal Use
Seedling bare root dip treatmentSeed treatment
Coating, DippingNursery bed treatmentRow treatment in widely spaced cropsSpot/basin area treatment in perennials
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Host Resistance
Effective, Economical and Environmentally safe
Steps involved in breeding a disease resistant varietyDevising techniques for assessment of
resistanceScreening of large germplasm, including wild
species in some casesStudy of inheritance of resistanceBreeding resistant lines through cross/back
cross, which have commercial traitsRigorous testing under field conditions 04/10/23Walia CCSHAU20
Nematode Resistant Crop VarietiesCrop Resistant Variety Nematode
Barley C-164, Rajkiran, BH-75 Heterodera avenae
Wheat Raj MR 1 Heterodera avenae
Citrus Trifoliate orange Tylenchulus semipenetrans
Coffee Robusta root-stock Pratylenchus coffeae
Potato Kufri Swarna Globodera rostochiensisG. pallida
Tomato SL-120, PNR-7, Hisar Lalit, Karnataka Hybrid, Mangla Hybrid
Meloidogyne spp.
Cowpea GAU-1 Meloidogyne spp.04/10/23Walia CCSHAU21
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Regulatory Method - Quarantine
Legal enforcement to prevent introduction or check further spread of pests/diseases
Directorate of Plant Protection, Quarantine and Storage (Ministry of Agriculture, GOI), through DIP ActInternational
Plant Protection Inspectors at all airports, seaports and landports for commercial material
Research material inspected by NBPGR, NBAGRDomestic
Golden Nematode of Potato included in DIP Act 197104/10/23Walia CCSHAU23
Biological ControlClassical biological control: Action of predators,
parasites and pathogens to control pestsAmbit of biological control expanded now-a-days
to include several other mechanisms, including antibiosis, host resistance etc.
Natural bio-control : Antagonistic biotic interactions among co-habiting natural populations of organismsIntroduced Biological Control
Inoculative releaseInundative release
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Nematode AntagonistsPredators
CollembolesTardigradesEnchytreidsProtozoaPredatory mitesPredacious nematodes
MononchusSeinura
Predacious fungi
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Predacious fungi
ExamplesSticky hyphae : StylopageSticky knobs: ArthrobotrysNon-constricting rings: DactylellaConstricting rings: Dactylaria 04/10/23Walia CCSHAU26
ParasitesFungi
Egg parasitesPaecilomyces lilacinusPochonia chlamydosporia (Verticillium
chlamydosprium)Female parasites
Nematophthora gynophilaVermiform stages
Catenaria
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ParasitesBacteria
Pasteuria penetrans
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Other Antagonists
BacteriaPseudomonas fluorescensBacillus subtilisAzotobacter chroococcumGlucoacetobacter diazotrophicus
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Integrated Nematode Management
INM seeks to stabilize pest nematode population below damaging levels (Pt) through integration of various unilateral and effective practices leading to a long-term package programme or schedule based on ecologically sound, economically viable and acceptable principles
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Integrated management of cereal cyst nematode (Heterodera avenae) on wheat
Rabi (November-April): Grow non-host crop such as mustard, chickpea Or
Grow resistant wheat (cv. Raj MR 1)/Barley (cvs. BH 393, RD 2035)
Kharif (July-October): Grow any crop
Summer (May-June): Two-three deep ploughings at 15 days’ interval
Field heavily infested with cereal cyst nematode found in the month of January/ February
Kharif: Grow any crop
Rabi: Grow non-host crop such as mustard, chickpea Or
Grow resistant wheat (cv. Raj MR 1)/Barley (cvs. BH 393, RD 2035) Or
If sowing of susceptible wheat cultivar an utmost necessity, apply carbofuran @1-2 kg a.i. per ha at sowing
Kharif: Grow any crop
Rabi: Monitor nematode population
Pi >2 J2/g soil Pi < 2 J2/g soil
Grow susceptible wheat
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Management of root-knot nematode (Meloidogyne spp.) in a vegetable cropping system (North Indian conditions)
Field heavily infested with root knot nematode
February: Transplant resistant tomato/ chillies or grow non-host crop such as cluster bean (vegetable variety)
July: Transplant treated nursery or grow okra/cucurbits with nematicidal seed treatment
October/ November: Grow onion / garlic/ marigold/ cauliflower
May: Raise susceptible tomato/ brinjal nursery with nematicidal treatment/ polythene mulching
May: Monitor RKN population in soil
Pi > 1 J2/g soil Pi < 1 J2/g soil
Take any susceptible vegetable crop