Verticillium Wilt in the UKProject Update

Dr Peter GladdersADAS UK Ltd

Review1. History in the UK

2. Disease surveys

3. Effects on yield

4. Varieties

5. Management options

2

Introduction - Verticillium wilt First confirmed in UK in 2007

Pathogen is Verticillium longisporum – specific for crucifers (mainly brassicas)

Important in other parts of Europe with up to 50% yield loss

Grey microsclerotia – key diagnostic feature

Look for long streaks right up the stem – phoma similar

Only evident late in season

HGCA Research Review No 72 completed May 2009

Disease Cycle of

OSR Verticillium

Wilt Plant debris or soil from nearby infested fields

Disease Survey Samples – Variation by Field & YearProportion of samples (fields) from Crop Monitor positive

for V. longisporumYear Samples examined Positive % positive

2009 95 10 10.52010 97 24 24.72011 100 12 12.0

Number of samples with various proportions (%) of stems positive

Year 0-5 6-10 11-15 16-20 21-30 31-40 41-50 51-60 >60

2009 3 2 0 0 0 3 0 1 1

2010 12 2 4 1 2 0 1 2 0

2011 2 3 0 0 1 3 0 0 3

Distribution of Verticillium Wilt 2009-2011

Factors affecting

distribution?

Rotations and Verticillium Wilt2010

Previous crop No. samples % crops % plants

Oilseed 0 0.0 0.0

Wheat – OSR – Wheat 5 40.0 3.1

Wheat - Wheat - OSR 13 30.8 2.3

Other cereal – Wheat - OSR 9 11.1 1.0

Other Cereal - Other Cereal - OSR 0 0.0 0.0

3 Previous Non OSR Crops 22 18.2 *

4 or More Previous Non OSR Crops 42 26.2 *

Other / Unknown info 6 33.3  

National 97 24.7 3.6

7

Yield Impacts Numerous reports of yield effects when crops ripen prematurely

2012 – significant yield impacts

Single plants harvested from heavily infected crops

Decreased TSW by 12-24% when verticillium affected >50% stem

Further losses if seeds are shed

Varieties Differ in their Resistance to Verticillium Wilt

Verticillium wilt at Bourne, Lincs 2010

0

5

10

15

20

25

30

Cat

ana

Ora

cle

Alie

nor

Com

pass

Pal

ace

Cui

llin

Kry

pton

Dim

ensi

on

DK

Cab

erne

t

Ham

mer

Ses

ame

PR

45D

03

PR

46W

21

Exc

el

Flas

h

PR

45D

05

NK

Bra

vour

PR

45D

06

Kal

if

Es

Ast

rid

DK

ExM

en

DK

Sec

ure

Cas

tille

Exc

alib

ur

% p

lant

s af

fect

ed LSD 10.2

Mean %verticillium by variety - Lincs 2010 & 2011(Limited variety experiments but main rankings have been consistent)

0

5

10

15

20

25

30

% v

ertic

illiu

m

AlienorCastilleCatanaCompassDimensionDK CabernetExcaliburFlashPalaceSesame

LSD = 9.9

Managing Verticillium Wilt - Options

1. Determine its prevalence on individual farms

2. Good agronomy – a strong plant holds off verticillium

3. Variety choice

4. Extended rotations

HGCA Project reference RD-2009-3618 Importance and management of Verticillium

wilt in winter oilseed rape

ADAS UK Ltd, Warwick-HRI, FERA, Farmacy/Hutchinsons