BOT 550 RECITATION – 2012 PERPLEXING POTATO PROBLEMS ...

BOT 550 RECITATION – 2012PERPLEXING POTATO PROBLEMSImpact of Nematodes on Potato Quality

PERPLEXING POTATO PROBLEMSImpact of Nematodes on Potato QualityColumbia Root-Knot Nematode(Meloidogyne chitwoodi)Northern Root-knot Nematode(Meloidogyne hapla)Southern Root-knot Nematode(Meloidogyne incognita)

ROOT-KNOT NEMATODE MELOIDOGYNE SPP.J2 find feedingsite in rootGrowth and moltingFeeding causes giant cellsJ2 J3 J4J2 migrate in soiland invade rootJ1 J2 in eggRoot forms gall around femaleFemale ruptures root, lays eggs

Symptoms of RootKnot NematodeOn Barley

Symptoms of RootKnot Nematodeon tomato

Root-knot Nematode Damage to CucumberCharles Averre

12001000Nematode Populations Only Needto Be Reduced to ThresholdTolerance LevelCROP VALUE ($)800600400200EconomicThresholdDensityNematode DamageFunction00.0 0.5 1.0 1.5 2.0 2.5 3.0 3.5LOG OF Pi (CONTROLLED POPULATION)

Columbia Root-Knot Nematodes (CRKN)Rarely Produce Aboveground Symptoms

Symptoms ofExternaland InternalDamage fromColumbiaRoot-KnotNematode(Meloidogynechitwoodi)

Tuber Infected WithMeloidogyne haplaNorthern Root-Knot Nematodes(Meloidogyne hapla) Don’t Gall TuberSurface But Do Produce Internal Spots

External & InternalSymptoms AreQuality DefectsTolerance For Defectsis Very LowIn Domestic Markets

As Few as 6 Visible Infection SitesCause Tubers to Be Culled.If the Crop Contains 5-15% Cullsit May Be Devalued or RejectedFrom Domestic Markets.

In Export Markets Where CRKN is Quarantineda Single Female Found in One TuberCan Result in Rejection of a Shipment.CRKN Infection Site

In 2005, 57 containers of chipping potatoeswere denied entry into South Koreadue to CRKN.Shipments of potatoes are occasionally deniedentrance into Mexico due to CRKN.

Ingham, unpublished dataMeloidogyne chitwoodi produces 3-4 generationson long season cultivars in warm growing regions.No population level can be left untreated!PERCENT CULLED TUBERS120100806040Russet Burbank Hermiston, OR - 2001 (2,075+ DD)Threshold densities are very low10% Culls = 0.4/250 g soil20Y = 90.6X/(3.04+X) R 2 = 0.66, P < 0.000100 20 40 60 80 100LIVE J2/250 G DRY SOIL AT PLANTING

Populations can reachdensities over 10,000/250 gsoil on long season hostcrops!Columbia root-knot nematodepopulations increase on hostcrops such as corn and wheatthat are grown in rotation withpotato.

Adult FemaleEgg mass ingelatinous matrix

SECOND AND LATER GENERATIONSINFECT ROOTS OR TUBERS

ROOT-KNOT NEMATODE IN POTATOBrownGelatinousMatrixBody of FemaleSantoTissue Reactionto Egg Mass

Discoloration is increased whenroot-knot infected potato tissue is fried

CURRENT KNOWN DISTRIBUTIONOF MELOIDOGYNE CHITWOODI IN USACALIFORNIA Nyczepir et al., 1984COLORADO Pinkerton and McIntyre, 1987IDAHO Nyczepir et al., 1984NEVADA Nyczepir et al., 1984NEW MEXICO Thomas et al., 2001OREGON Nyczepir et al., 1984TEXAS Szalanski et al., 2001UTAH Griffin and Thompson, 1986WASHINGTON Nyczepir et al., 1984

PERPLEXING POTATO PROBLEMSImpact of Nematodes on Potato QualityStubby-root Nematodes (SRN)Paratrichodorus & Trichodorus spp.

LIFE STRATEGIES OF NEMATODESROOT PATHOGENSMigratory Ectoparasites - feed outside of root, movecell-to-cell but do not enter root. e.g., dagger nematodeStyletHead

PERPLEXING POTATO PROBLEMSImpact of Nematodes on Potato QualityStubby-root Nematodes (SRN)Paratrichodorus & Trichodorus spp.- Feed on surface cells of rootsAnd perhaps tubers- Cause no significant damage to potato- Vector tobacco rattle virus (TRV),which causes corky ringspot disease (CRS)also referred to as spraing

Stubby-root Nematode(Paratrichodorus & Trichodorus spp.)Ingest TRV particlesin infected cytoplasmEsophagusSolid, curved stylet punctures rootcells like daggerCell sap runs down groove in styletinto esophagus

Red = Area of Virus Retention inTrichodorus & ParatrichodorusVirus particles are introducedto plant cellswith predigestive saliva

Both have to be “packaged”together to allow for virustransmission by the nematode

Stubby-root Nematodes and TRVRarely Produce Aboveground Symptoms

Ranger Russet Tubers Infected with TRV

SYMPTOMS OF CORKY RINGSPOTSPOTSARCS

Symptoms VaryWith VarietyArcs and ringsin Yukon GoldDiffuse spots inRusset Burbank

Internal Symptoms Caused by TRVConfused with:Alfalfa Mosaic VirusPotato Mop Top VirusTomato Spotted Wilt VirusPotato Virus Y ( NTN, N:O )Physiological Issues

Necrotic arcs and spots are consideredquality defects by the potato industry andtubers with even small amounts ofsymptoms are graded as culls.Crops with more than 6% culls may bedowngraded or rejected.

TREAMENT THRESHOLDSSTUBBY-ROOT NEMATODESPARATRICHODORUS SPP.- IF TRV IS NOT PRESENT, POPULATIONDOES NOT HAVE TO BE CONTROLLED- IF TRV IS PRESENT, ALL STUBBY-ROOTNEMATODES MUST BE CONTROLLED- SYMPTOMS RESULTING IN COMPLETECROP LOSS OCCUR AT 3/250 G SOIL

Corky Ringspot in the United StatesSeveral western states - Vector is P. alliusFlorida – Vector is P. minorMichigan, Minnesota, Wisconsin – Vector unidentified

PERPLEXING POTATO PROBLEMSImpact of Nematodes on Potato QualityManagementHow to manage nematode diseaseswhere there is no threshold.How to manage CRS and CRKN wherethey occur together.

METAM SODIUM APPLIED THROUGHCHEMIGATION IN 1/2 - 1 IN WATERCAN NOT CONTROL CRKN OR CRS!

Shank Injection of Metam SodiumAt 6, 12, and 18 inchesCan Suppress CRKN & CRS

Injecting Metam Sodium with EthopropAt 6 and 12 inchesImproved Control of CRKN

Shank Injection of 1,3-Dichloropropene at 18 in.Controls CRKN and CRSMost of the Time

Provides ExcellentControl of CRKN & CRSBut….ExpensiveHealth ConcernsShortage of 1,3-DShank Injection of1,3-D plus Water-runor Shanked Metam

Oxamyl is a liquidapplied in water:- In-furrow at planting- Banded or chemigatedat emergence-Chemigated duringseason

CRKN & CRS Can Be Managed With OxamylBut Application Timing is CriticalBecause of Short Half-Life

MELOIDOGYNE CHITWOODI POPULATIONDEVELOPMENT AND DEGREE DAYACCUMULATION IN FIELD-GROWN POTATO70006000PROSSER, WA 19855000400030002000FIRST J2IN TUBERSNEW J2 INTUBERS10000TUBERINITIATION0 500 1000 1500 2000 2500DEGREE-DAYS (BASE 5 C)Pinkerton et al., 1991

Benefit of Oxamyl In-Furrow% Tuber CRKN infection after incubation(= most sensitive assay)W/O IF With IFExample 1-2002 56 9Example 2-2002 22 1Example 3-2003 15 2Example 4-2004 44 1Example 5-2004 83 21In-Furrow may be the most effective treatment period.

% No. 2 & CULLED TUBERSOnly Early Season Applicationsof Oxamyl Control CRS35302520151050NONE 55, 69, 83 41, 55, 69, 83 0, 55, 69, 83 0, 41, 55, 69, 83APPLICATION TIMES IN DAYS AFTER PLANTINGIngham et al, 2004

Crop Rotation = ChallengeCRKN, SRN and TRV Have Wide Host RangePlanting Nonhost Cash Crops and GreenManure Crops Before Potato Can SuppressDamage from CRKN But Demand for TheseCrops is Limited.Rotation is Less Effective for CRS because ofWide Host Range of TRV in Crops andWeeds.

CRKN AND NEMATODE-CULLED TUBERSIN SELECTED CROPPING SEQUENCESJ2/250 G SOIL % CULLS2001 2002 2003 4/24/01 4/20/04 10/4/04W-Cl FC FC 970 1,990 100W-M SSC-R GP-LB-MB 760 2 11FC 1 SSC-R GP-LB-MB 1,340 3 9FC 1 W-R GP-LB-MB 1,600 3 2SSC-TF----------------MB 1,350 0* 2W=Wheat, FC=Field corn, SSC=Supersweet cornGP-LB=Green Pea-Lima bean double crop, TF=2 yrs Tall FescueGreen manure cropsCl= Clover, M=Mustard, R=Radish, MB=Mustard blend1Average Mc Population at 2001 Harvest was 10,690/250 g soil

% Tubers With CRSAlfalfa Can Cleanse Paratrichodorus alliusof TRV But Must Be Weed FreeTreatment Before PotatoBoydston et al. 2009

EFFECT OF ALFALFA CV LAHONTONON ROOT-KNOT NEMATODESReproductive Index (Final/Initial)after 3 YearsMeloidogyne hapla 4.8M. chitwoodi race 1 0.2M. chitwoodi race 2 30.7Ingham 1991

Green Manure Cover CropsCan Suppress CRKN and SRNCanolaWet Fallow RadishMustardSudangrass

%TUBERS WITH 6+ CRKNEFFECTS OF GREEN MANURE CROPSON TUBER DAMAGE BY CRKNColumbia Basin, Oregon1009080706050403020100ABILITY OF GREEN MANURE CROPSTO SUPPRESS CRKN VARIES GREATLYAND IS CONSTANTLY IMPROVING***CLOVER ARUGALA CAL 119 MUSTARD TRUDAN SORDAN CAL 61GREEN MANURE CROP(Planted Fall Before Potato Crop)

Magnitude of ChangeSRN Population Change from GMPlanting to Potato Planting (’07-’08)5.04.54.03.53.02.52.01.51.00.50.0Sordan***53 41ArugulaColonelWheelerCal.61YamhillCal.199R VALUEDoubletTerranova

% Tuber w/any CRSEffects of GM Crops on Tuber CRS50454035302520151050***SordanCal.199YamhillArugulaTerranovaDoubletColonelCal.61Wheeler

ResistanceAll Current Commercial Cultivars areSusceptible to CRKN.Shorter Season Cultivars Express FewerSymptoms Since Fewer Degree-Days SupportLess Nematode Development.Early Harvest = Less Damage!

% SERIOUS DAMAGE & CULLSDifferent Varieties May Have DifferentSensitivity to CRS Symptom ExpressionCultivar Selection may Depend on Virus Strain Present

% Tubers With DamageClones In Variety Development ProgramWith “Resistance” to CRKN or TRVBrown et al. (unpublished data)

PERPLEXING POTATO PROBLEMSImpact of Nematodes on Potato QualitySummaryColumbia root-knot Nematode and TRV,Vectored by Stubby-root Nematode, CauseQuality Defects Resulting in Crop Rejectionat Very Low Population Densities.

PERPLEXING POTATO PROBLEMSImpact of Nematodes on Potato QualitySummaryDouble Fumigation with 1,3-D and MetamSodium is the Best Control.Oxamyl can be Effective for Fields With LowPopulations but Applications Must Begin Early.

PERPLEXING POTATO PROBLEMSImpact of Nematodes on Potato QualitySummaryCultural Strategies Could Probably beCombined to Suppress CRKN and CRS-Weed-free Nonhost Crops-Green Manure Crops-Planting Less Susceptible VarietiesWhat May Work for CRKN May Not for CRSDevelopment of Resistant Varieties Will ImproveControl in The Future.