Introduction to Plant Introduction to Plant Parasitic Parasitic Nematodes and Nematodes and Their ManagementTheir Management

Jimmy R. Rich and Stanley B. Jimmy R. Rich and Stanley B. HendleyHendleyIFAS/NFRECIFAS/NFRECUniversity of FloridaUniversity of Florida

NematodesNematodes

• Phylum NematodaPhylum Nematoda• RoundwormsRoundworms• Microbial FeedersMicrobial Feeders

• (90% plus)(90% plus)• Animal ParasiticAnimal Parasitic• Human ParasiticHuman Parasitic• Insect ParasiticInsect Parasitic• Plant ParasiticPlant Parasitic

Interesting FactsInteresting Facts

• Most numerous Most numerous animalanimal

• Second most Second most numerous speciesnumerous species

• Size: mostly Size: mostly microscopicmicroscopic

• Longest is 26 feet (in Longest is 26 feet (in Blue whale)Blue whale)

• Simple morphologySimple morphology• No circulatory systemNo circulatory system• No respiratory systemNo respiratory system• No skeletonNo skeleton

Examples of Non-Plant-Examples of Non-Plant-Parasitic NematodesParasitic Nematodes• Animal ParasitesAnimal Parasites

Canine heart worms,Canine heart worms,AscarisAscaris

• Human ParasitesHuman Parasitespinworms,pinworms,hookwormshookworms

• Insect ParasitesInsect Parasitesmosquitoes, molemosquitoes, molecrickets, citrus crickets, citrus

weevilsweevils

Plant-Parasitic Plant-Parasitic NematodesNematodes• Over 6000 known Over 6000 known

speciesspecies• Present in all ecological Present in all ecological

nichesniches• Attacks almost all plantsAttacks almost all plants• Cause 10% losses to Cause 10% losses to

cropscrops• Reduces ornamental Reduces ornamental

growthgrowth• Serious turf problemsSerious turf problems• Big problem on tree Big problem on tree

cropscrops

MorphologyMorphology• A nematode has:A nematode has:

• Digestive Digestive organsorgans

• Reproductive Reproductive organsorgans

• Excretory Excretory structuresstructures

• MusclesMuscles• NervesNerves• Tough skin or Tough skin or

“Cuticle”“Cuticle”

Plant-parasitic nematodes all havestylets (spears) that penetrate cells

and withdraw the contents.

NematodeNematode Names Names• Plant nematodes have both Plant nematodes have both commoncommon

and and scientific scientific names, some of names, some of economical importance, by common economical importance, by common name, are:name, are:

Root-knot, Sting, Stubby-root, Reniform, Root-knot, Sting, Stubby-root, Reniform, Lance, Ring, Lesion, Burrowing, Citrus, Lance, Ring, Lesion, Burrowing, Citrus,

Spiral, and CystSpiral, and Cyst

Feeding HabitsFeeding Habits

Nematodes may be grouped by feeding habit Nematodes may be grouped by feeding habit as: as:

• EndoparasiticEndoparasitic– entire body inside the root– entire body inside the root• EctoparasiticEctoparasitic– entire body outside the root– entire body outside the root• Semi-endoparasiticSemi-endoparasitic- part of body inside root - part of body inside root By movement when feeding, they are called:By movement when feeding, they are called:• SedentarySedentary – mostly immobile during their life – mostly immobile during their life• MigratoryMigratory – mobile for all their life. – mobile for all their life.

Feeding Habits of Some Feeding Habits of Some Plant-parasitic Plant-parasitic

NematodesNematodes

Root-knot

Lesion

Cyst

Feeding Habits of Some Feeding Habits of Some Plant-parasitic Plant-parasitic

NematodesNematodesRing

Feeding Habits of Some Feeding Habits of Some Plant-parasitic Plant-parasitic

NematodesNematodes

Stubby root

Reniform

Nematode DamageNematode Damage

• Nematodes damage plants by Nematodes damage plants by reducing or modifying root massreducing or modifying root mass

• Root cells are killed or modified to Root cells are killed or modified to serve as food for the nematodeserve as food for the nematode

• Typical root and foliar symptoms Typical root and foliar symptoms resultresult

• Water and Nutrient Stress –Water and Nutrient Stress – • Premature WiltingPremature Wilting• Leaf Yellowing (Chlorosis)Leaf Yellowing (Chlorosis)• Plant StuntingPlant Stunting• Irregular Symptom PatternsIrregular Symptom Patterns

Foliar Damage Foliar Damage SymptomsSymptoms

Foliar Foliar Symptoms-Symptoms-Aerial ViewAerial View

Foliar Symptoms – Foliar Symptoms – Oval PatternOval Pattern

Foliar Symptoms-Foliar Symptoms-Plant DeathPlant Death

Foliar Symptoms-Foliar Symptoms-StuntingStunting

Foliar Symptoms-Foliar Symptoms- Leaf Yellowing Leaf Yellowing

Foliar Symptoms-Foliar Symptoms-StuntingStunting

Foliar Symptoms- Foliar Symptoms- Slow DeclineSlow Decline

Foliar Symptoms-Foliar Symptoms-TopplingToppling

Root Root DamageDamage SymptomsSymptoms• Galled RootsGalled Roots• Stunted RootsStunted Roots• Swollen Root TipsSwollen Root Tips• Root LesionsRoot Lesions• Increase in Lateral RootsIncrease in Lateral Roots

Root Symptoms- GallingRoot Symptoms- Galling

Root Symptoms- Cyst Root Symptoms- Cyst Nematodes on RootsNematodes on Roots

Root Symptoms- Root Symptoms- Peanut Pod Galling Peanut Pod Galling

Root Symptoms-Root Symptoms-Lesions Lesions

Root Symptoms –Root Symptoms –Sweet PotatoesSweet Potatoes

Root Symptoms -Root Symptoms -Irish PotatoesIrish Potatoes

Root Symptoms-Root Symptoms-Potato Rot NematodePotato Rot Nematode

Root Symptoms- Root Symptoms- SpranglingSprangling

Disease InteractionsDisease Interactions• Nematodes cause plant disease and can Nematodes cause plant disease and can

make fungal and bacterial diseases worse.make fungal and bacterial diseases worse.

An example is Fusarium wilt where root-knot An example is Fusarium wilt where root-knot nematodes create entry points for the fungus.nematodes create entry points for the fungus.

Control Fusarium(F) Mi +(F) Mh +(F) Mj +(F)

Problem IdentificationProblem Identification

• Combinations of:Combinations of:• Foliar SymptomsFoliar Symptoms• Roots SymptomsRoots Symptoms• Cropping HistoryCropping History• Laboratory AnalysisLaboratory Analysis

Sampling BasicsSampling Basics

• County Agents haveCounty Agents have kits availablekits available• Sample 10”-12” deep; in turf 4”-6”Sample 10”-12” deep; in turf 4”-6”• Sample only in moist soils –Sample only in moist soils – Not dry or wetNot dry or wet• Use aUse a plastic bagplastic bag onlyonly• Do not let the sample get too hot or coldDo not let the sample get too hot or cold• Send Send 1 pint of soil1 pint of soil and and 1 cup of roots1 cup of roots• Send for extractionSend for extraction ASAPASAP• Do not allow samples to become hot or Do not allow samples to become hot or

frozen, either way nematodes frozen, either way nematodes will be killedwill be killed

ManagementManagement Methods Methods

• ExclusionExclusion• SanitationSanitation• Rotation Rotation • Plant Resistance Plant Resistance • Fallow Fallow • SolarizationSolarization• Nematicides Nematicides

Exclusion/SanitationExclusion/Sanitation

• Buy or grow transplants that are Buy or grow transplants that are nematode-free. nematode-free.

• Use nematode-free soil or potting Use nematode-free soil or potting medium medium

• Clean tools and equipment when Clean tools and equipment when changing areas or fieldschanging areas or fields

• Remove infected plant roots Remove infected plant roots

RotationRotation

• Move garden to a new location Move garden to a new location • Rotate grasses with broadleaf plantsRotate grasses with broadleaf plants• Plant cover crops that are poor hostsPlant cover crops that are poor hosts• Keep weeds in check, many are hosts Keep weeds in check, many are hosts

• Maintain high organic matter levels Maintain high organic matter levels • Irrigate frequently and use higher Irrigate frequently and use higher

fertilizer ratesfertilizer rates

Soybean RotationSoybean Rotation

ResistanceResistance

• Resistance breeding has been mainly to Resistance breeding has been mainly to root-knot nematode root-knot nematode ((Meloidogyne spp.Meloidogyne spp.))

• Resistance, however, may be to only 1 Resistance, however, may be to only 1 root-knot speciesroot-knot species

• Examples of resistance can be found in Examples of resistance can be found in tomato, snap bean and some southern tomato, snap bean and some southern peaspeas

• Little resistance is available to other Little resistance is available to other nematode speciesnematode species

Resistant/Not ResistantResistant/Not Resistant

SolarizationSolarization• Only works moderately well with Only works moderately well with

nematodesnematodes• Has added advantage of reducing Has added advantage of reducing

weed problemsweed problems• Use clear plastic, make sure soil is Use clear plastic, make sure soil is

tilled and moisttilled and moist• Use in the hottest months and leaveUse in the hottest months and leave 6-8 weeks6-8 weeks

Solarization- Solarization- Laying Clear PlasticLaying Clear Plastic

Fallow

Sanitation

Solarization

Resistance

Chemicals

Rotation

SuccessfulSuccessfulNematodeNematode

ControlControl

Fallow

Solarization

Rotation

Management SummaryManagement Summary

• No No singlesingle practice will practice will control control nematodes, so nematodes, so two or more two or more control methods control methods must be used.must be used.

SuccessfuSuccessful l

Nematode Nematode ControlControl

Sanitation

Chemicals

Resistance

FAQ - Organic MatterFAQ - Organic Matter

Does compost and organic Does compost and organic matter control nematodes?matter control nematodes?• The answer is generally The answer is generally nono, ,

however, they increase water and however, they increase water and nutrients available to the plant.nutrients available to the plant.

• Thus a healthier plant can tolerate Thus a healthier plant can tolerate more nematode damage.more nematode damage.

FAQ - ResistanceFAQ - Resistance

My nematode ‘resistant’ plant still had My nematode ‘resistant’ plant still had lots of nematode damage?lots of nematode damage? • A resistant plant is ‘resistant’ to only a A resistant plant is ‘resistant’ to only a

nematode to which it was bred nematode to which it was bred

• For example, a plant may be For example, a plant may be resistant to only one type (specie) resistant to only one type (specie) of nematode but not others of nematode but not others

Do nematodes cause damage Do nematodes cause damage under both wet and dry under both wet and dry conditions?conditions?• Greatest damage is caused Greatest damage is caused

when conditions are dry.when conditions are dry.• Wet conditions mask some Wet conditions mask some

damage until root rotting from damage until root rotting from nematode damage begins.nematode damage begins.

FAQ – Wet or DryFAQ – Wet or Dry

FAQ - NematicidesFAQ - Nematicides

What is the best ‘nematicide’ What is the best ‘nematicide’ available for nematodes?available for nematodes?• All effective nematicides are All effective nematicides are

restricted use chemicals and cannot restricted use chemicals and cannot be bought without a pesticide licensebe bought without a pesticide license

• Products found in garden stores are Products found in garden stores are ‘at best’ nematode suppressants.‘at best’ nematode suppressants.

• Generally, these products are not Generally, these products are not recommended for nematode controlrecommended for nematode control

FAQ - FallowFAQ - Fallow Is fallow recommended for nematode Is fallow recommended for nematode

management?management? • Fallow makes sense because, if nematodes Fallow makes sense because, if nematodes cannot feed, they will starve, however: cannot feed, they will starve, however: • Many weeds are host to nematodes,Many weeds are host to nematodes,

thus they must not be allowed to grow.thus they must not be allowed to grow.• At least one growing season of fallow must At least one growing season of fallow must

be be used and fallow depletes soil organic matterused and fallow depletes soil organic matter

• During the ‘winter’, most nematodes are During the ‘winter’, most nematodes are

relatively dormant and do not feed anyway. relatively dormant and do not feed anyway.

UF/IFAS EDIS UF/IFAS EDIS PublicationsPublicationshttp://edis.ifas.ufl.edu/TOPIC_Nematodeshttp://edis.ifas.ufl.edu/TOPIC_Nematodes • General Nematology General Nematology • Nematodes in the YardNematodes in the Yard• Lawn Pest NematodesLawn Pest Nematodes• Landscape NematodesLandscape Nematodes• Urban Tree Pest NematodesUrban Tree Pest Nematodes• Vegetable NematodesVegetable Nematodes• Fruit Pest NematodesFruit Pest Nematodes

Authors: Jimmy Rich and Stanley Hendley; Authors: Jimmy Rich and Stanley Hendley; for comment or information, please for comment or information, please contact contact jrich@ifas.ufl.edujrich@ifas.ufl.edu

Photo Credits: R. P. Esser, R. S. Hussey, W. Photo Credits: R. P. Esser, R. S. Hussey, W. F. Mai, R. A. Motsinger, A. W. Johnson,F. Mai, R. A. Motsinger, A. W. Johnson,

D. W. Dickson, A. Steele, H. L. Rhoades,D. W. Dickson, A. Steele, H. L. Rhoades, M. A. McClure, J.D. Eisenback, K. R. Barker M. A. McClure, J.D. Eisenback, K. R. Barker

Entomology and Nematology Department Entomology and Nematology Department Copyright University of Florida 2003Copyright University of Florida 2003