NEW ZEALAND WINEGROWERS FACT SHEET

BLACK FOOT IN GRAPEVINE NURSERIES

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Figure 2. Broken off roots on graftling create potential entry for Black foot.

Figure 1. Base of callussed graftling showing potential entry for Black foot.

Figure 3. Stem base showing dark internal rot caused by Black foot.

AUGUST 2013 - NZTD103 TRUNK DISEASES

KEY NOTES

• Blackfootisalowertrunkdiseaseof

grapevinescausedbyCylindrocarpon

fungi.

• Theinfectiouspathogenscansurvive

insoilaftertheremovalofinfected

grapevinesorotherhosts.

• Canesusedforgraftingarerarely

infectedbutmaybecontaminatedby

lyingonsoil.

• Mustardplantsormustardseed

mealcultivatedintosoilcanreduce

pathogenlevels.

• Dormantgraftednurseryvinescanbe

hotwatertreatedbeforedelivery.

SYMPTOMS

Graftedvinesoftenshownosignificant

symptomswhileinnurseryplots

becauseearlyinfectionshavenotyet

causedseriousdamage.Sometimesthe

vinesmayshowsignsofwaterstress

andbestuntedwithchloroticleaves,

withuprootedplantsshowingreduced

rootandshootmass.Whendissected

longitudinally,theinternalwoodtissues

canappearpinkishorpurplish;this

tissuelaterdevelopsintodarkstreaks

orpatches.Blackfootsymptomsoften

appearnearthebaseoftherootstock

wherethepathogenhasinvadedthe

trunk.

DISEASE CYCLE

TheCylindrocarponspeciesthatcause

Blackfootpersistinrootfragments

oraschlamydospores(restingspores)

thatcansurviveinsoilforseveralyears

aftertheirgrape,fruitandforestryhosts

areremoved.Healthyplantsplacedin

infestednurserysoilcanbecomeinfected

throughrootortrunkwounds,suchas

theincompletelycallusedrootstock

end,damagebysoilinsectsorbyroot

breakagesaftercallusingorplantlifting.

Plant-to-plantspreadislikelyviaadjacent

infectedrootsorbymovementofspores

indrainagewater.Useofthesameland,

yearafteryear,willincreasethespore

loadofthesoilandsoincreasethe

proportionofinfectedplants.Infection

withintrunktissueprogressesupwards

inadark,spreadingblockwhichkillsthe

vasculartissue.Thisusuallykillsthevine

beforeitcanreachanyshoots,soshoot

infectionisrare.However,harvested

caneslaidonsoilbeforecollectionmay

becomecontaminatedwiththepathogen,

whichgainsentrythroughrecentwounds.

Harvesteddormantplantsmaybecome

infectedfromattachedsoil.

CONTROL

Individiualcontrolmethodsarenot100%

effective,soseveralmethodsshouldbe

integratedintoanurserymanagement

programme.

Soil moisture:Plantingsitesshouldbe

well-drainedbecauseincidenceofBlack

footisusuallygreaterinwetsoils.

Preplanting methods:

1. Rotateplantingsitesforoneyearby

restingthesoilorgrowinganother

cropbetweenuseasnurserybeds.Ifa

mustardcropisgrownuntilflowering,

onceortwice(successively),withthe

cropincorporatedintothesoileach

time,thiswillbio-fumigatethesoil.

2. Ifitisnotpossibletorestthesoilfor

oneyear,thenincorporatemustard

plantsasaboveormustardseedmeal

(160g/m2)betweenplantharvesting

inwinterandplantinginspring.

NEW ZEALAND WINEGROWERS FACT SHEET

©NewZealandWinegrowers2013

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CONTACT: NewZealandWinegrowersnzwine.com093033527

AUGUST 2013 - NZTD103 TRUNK DISEASES

Figure 4. Sections through dormant rooted plant from nursery infected vine that has developed a second tier of roots due to Black foot disease.

Sanitation:

1. Graftingmaterialshouldbetreatedin

fungicidesolution(Sporekill™at150

mL/100Lwater)foratleastonehour

soonafterharvesting,thendrip-dried

andcoolstored.

2. Graftingareasshouldbecleanedand

disinfecteddaily(withfungicideor70%

ethanol).Tables,graftingequipment

andstaffhandsshouldbefrequently

washedanddisinfected.

3. Graftedjoinsshouldbedippedinwax

thatcontainsafungicideassoonas

possibleaftergrafting.

4. Duringcallusing,sanitarymeasures

shouldbeusedtoensurethatcallus

cratesandcallusmediaarefreeof

thesepathogens.Cratesandmedium

shouldbesterilised,e.g.withsteam.

Callussingmediummayalsobetreated

withcaptan,iprodioneorTrichoflow™.

Hot water treatment:

Dormant,harvestednurseryvinescanbe

hotwatertreated(50ºCfor30minutes

followedby60minutesincoldwater).

Thisprovides100%control,without

significantreductionsinsubsequent

buddingorgrowthrate.

Rootstock varieties:

Insoilswithheavydiseasepressure,

Ripariagloire,3309and5Cvineshave

demonstratedmoreresistancethan101-14

andSchwarzmann,buttherewaslittle

differencebetweenrootstocksinsoils

withlowdiseasepressureandnonewere

completelyresistant.

ACKNOWLEDGMENT

ThisfactsheetwaswrittenbyDrMarlene

Jaspers,LincolnUniversity.Funding

forthisstudywasreceivedfromNew

ZealandWinegrowersandFRST(Tertiary

IndustryFunding).

DISCLAIMER

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thisfactsheetNewZealandWinegrowers

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