EARLY BLIGHT

potato.ro

EARLY BLIGHT

Plant Breeding and Acclimatization Institute - Radzików

DEPARTMENT OF

POTATO PROTECTION AND SEED SCIENCE – BONIN,

POLAND

Józefa Kapsa

Important threats in

potato production and

integrated pathogen/pest

management

17 th Trienial Conference of EAPR

6-10 July 2008, Brasov, Romania


Region

Potato production and consumption, by region

Harvested area Quantity Yield Consumption

hectares tonnes tonnes/hectare total food (t) kg per capita

Africa 1 499 687 16 420 729 10.95 12 850 000 14.18

Asia/Oceania 9 143 495 131 286 181 14.36 101 756 000 25.83

Europe 7 348 420 126 332 492 17.19 71 087 000 96.15

Latin America 951 974 15 627 530 16.42 13 280 000 23.65

North America 608 131 24 708 603 40.63 19 156 000 57.94

WORLD 19 551 707 314 375 535 16.08 218 129 000 33.68

Source: FAOSTAT


Tuber yield losses caused by late blight (Phytophthora ( Phytophthora infestans) infestans

Worldwide average losses on unprotected fields in tuber

yield due to LB 70% (Hoffman i Schmutterer 1983)

with early disease outbreak even 100% (Fry 1994)

In Poland yield losses resulting from P. infestans infection are

estimated in a range of 20 - 25% (Pietkiewicz 1989)

In the years 1999–2003 the yield losses were higher and ranged from

22 to 57%, 57% , average 39,4% (Kapsa 2004)


The earlies

infections

in season 20.04 2

at field

crops

Y e a r s

1998 1999 2000 2001 2002 2003 2004 2005 2006

early

04 2

1 – covered crops, 2 – waste piles

Dates of the first recorded outbreaks

of late blight in potato in Europe

(data from 17 European countries - www.euroblight.net)

30.04 2

early

04 2

10.04 1 1 21.04 06.05

06.05 1,2

04.04. 18.05.

1,2 04.04

10.05. 08.05. 11.05. 14.05. 02.05. 06.05. 13.05. 04.04. 04.04 24.05.


seed tubers

oospores

Importance of various sources of

primary LB infection

waste piles

potato field

other potato fields

volunteer


Incidence of stem blight

on potato crops in Poland

Year Number of monitored fields

Percentage of crops with stem

blight symptoms

1997 149 80,5

1998 158 65,2

1999 76 72,4

2000 56 58,9

2001 51 68,6

2002 64 73,4

2003 34 35,3

2004 17 47,1

2005 21 47,6

2006 17 29,4

2007 15 43,8

Σ /mean mean 658 56,6


Losses of the yield due to early blight

First information about losses: 10-32% (Neergaard 1945)

10- 0-57% 57% (Harrison et al. 1965)

SU - 25%, locally 60% (Bacanov 1970, Dorożkin 1972)

Average losses in USA 20-30% (Johnson et al. 1986, Fry 1994),

up to 50% Hadders (2002)

In Brazil losess up to 73% (Brune, et al. 1998)

In South Africa up to 50% (Denner & Theron 1999)

In Poland 10-32% (Kuczyńska 1992), 6-45% (Kapsa & Osowski 2004)


EARLY BLIGHT - Alternaria species

The fungus was described for the first time in potato -

late in the 19th century (Ellis & Martin, 1882)


Factors affecting early blight development

- Alternating wet/ dry periods

- Wind borne spores

- Factors influenced on plant weakness.

- senescing plants

- soil with low contents of organic matter

- low nitrogen fertilization

- other pathogens’ infection

Potato plants infected with some viruses are

more susceptible to the early blight infection

This refers mainly to viruses PVY, PLRV and

PVX


Fungal species

/synonyms

Alternaria solani

Macrosporium solani

A.porri f.sp.solani

A.dauci f.sp.solani

Alternaria alternata

A.tenuis

Torula alternata

Characteristic of two Alternaria species,

the casual agents of potato early blight

Host

plants

plants

from

Solanacea

except

Datura

about 40

plant

species

Source: * Dorozkin, Bel’skaja 1979

** Hooker 1990

Disease

symptoms

Early blight

Brown leaf spot

Optimum

temperature -

0C*

Sporulation

- temp. 26-28 0 C

Mycelium growth &

spore germination

– 18-22 0 C

Sporulation

- temp. 25-26 0 C

Mycelium growth &

spore germination

– 22-26 0 C

Spore

morphology**


Year

Incidence of EB symptoms at potato fields in Poland

Number of

observed fields

Percentage of fields

with early blight

1998 138 78,3

Term of e.b. appearance

(mean number

DAP*)

78,3 60

1999 93 88,0 65

2000 56 91,1 57

2001 50 96,0 61

2002 64 90,6 56

2003 34 85,0 63

2004 25 80,0 65

2005 21 86,0 54

2006 19 78,9 67

2007 16 87,5 58

∑ / x 516 86,1 61

* DAP = number of days after planting


Potato field destroyed

by black dots

Black dot – Colletotrichum coccodes

symptoms on potato stem

infected daughter tubers

S y m p t o m s

black dot – fungus acerwuli

sklerotia on tuber skin


Conditions favorable to bacterial diseases


Blackleg and tuber soft rot

� Pectobacterium atrosepticum

�Pectobacterium carotovorum ssp.carotovorum

�Pectobacterium chrysanthemi (syn. Dickeya spp.)

spp

D.dadantii

D. zeae

D. dianthicola


yellow areas between leaf veins

Potato bacterial ring rot (Clavibacter

michiganensis ssp. sepedonicus)

marginal necrosis on rolling leaves

brown necrosis in the vascular ring

cracks on surfaces of tubers


willting of the upper leaves

Brown rot, rot,

bacterial wilt

- Ralstonia solanacearum

solanacearum

www.potato.org.uk

initial browning of the vascular

ring at the stolen end

cremy white bacterial slime from cut vessels at stems & tubers

www.potato.org.uk


Characteristic Ring Rot Brown Rot

Name of pathogen

Clavibacter sepedonicum

ssp. michiganensis

Ralstonia solanacearum

Gram stain positive negative

Bacterial

excudate

S

Y

M

P

T

O

M

S

condition

from vascular tissue usually

with squeezing

from vascular tissue abundant

droplets, droplets usually without squeezing

colour milky white grayish white

plant wilting

vines

vascular

tissue

Diferences between bacterial diseases

initial symptoms as wilting of

the lower leaves

chlorosis or yellowing, yellowing later

necrosis between leaf veins

discoloration in stems, often

indistinct

wilting by rapid colapse, starting at

the upper leaves

green, green relatively free from chlorosis

distinct browning usually evident in

stems

tubers cracks sufaces usually not cracked

tuber eyes free from adhering soil excudate causes soil to adhere


Common scab – Streptomyces spp.

The common scab is caused by bacteria

belonging to the genus Streptomyces:

S.scabies

and new species: S. europaeiscabies

S. stelliscabies

netted scab pathogens: S. reticuliscabies

S. europaeiscabies


stem canker

sprout pruning

black scurf

rolling leaves

Rizoctonia

– Rhizoctonia solani

tuber deformation

aerial tubers

mycelium on stem base


Potato tuber diseases

tuber late blight

silver scurf

bacterial soft rot

black scurf

Fusarium dry rot

common scab


Silver scurf – Helminthosporium solani

light brown spots

dark brown spots

autumn

winter

spring

distinct silvery sheen

fungus sporulation


Powdery scab - Spongospora subterranea

Powdery scab causes the formation of superficial pustules

that release spores into the soil

The powdery scab pathogen causes

the formation of small galls on roots


PLRV

Viruse diseases

PVY N

PVY


Pests in potato crops


Insect soil pests in potato crops

Wireworms- Wireworms the larvae of click

beetles (Coleoptera: Elateridae)

Cutworms Cutworms-

the larvae of

Nuctuidae


Problems in protection ???

Potato is planted, harvested, stored and consumed

mainly in the vegetative form – the the

tuber.

In this respect the potato crop is

different from most major arable

crops and creates (imposes)

special crop protection problems.


Pathogen/ pest management strategy

BEST PRACTICES IN THE CONTROL

STRATEGIES FOR PATHOGEN / PEST CONTROL

1. Previous crop and decisions decisions

before planting

2. Control activities during planting

3. Control of agrophages during growing season

4. Harvesting

5. Potato storage management


Pathogen/ pest management strategy-1

1. Previous crop and decisions decisions

before planting

� crop rotation

� soil type

� optimal fertilization

� weed control

� choice of cultivar

2. Control activities during planting

� seed health

� acceleration of plant sprouting in potato crops

� seed and /or soil treatments

� Formation of ridges


Pathogen/ pest management strategy -2

3. Control of agrophages during growing season

� eliminate of pathogen /pest sources

- potato dump hygiene

- control of volunteer potatoes

- negative selection

� irrigation

� chemical control

- forecasting and monitoring

- DSSs

- choice of product

- haulm destruction

ARV = 130


Country

The estimated use of fungicides to control of P.infestans

Average number sprays in season

1997 1998 1999 2000 2001 2002 2003 2004

(www.euroblight.net)

200

5

2006

Belgium 14-15 12-14 10 12-20 11-13 12-14 11 15 16 12-16*

Denmark 5.5 8 7.5 7-8 8-9 8-9 7 7-8 7-8 5-16

France 10-14 ? 15 16-17 10-19 12-13 10-14 ? 8-13 8-18*

Germany 7-9 3-10 4-5 2-14 2-16 3-14 3-11 2-10 1-10 4-12*

UK: England,

Wales, Scotland 4-18 8-15 4-16 ? 8-12 8-14 9,9 11-12 10-11 8-12

UK: N.Ireland 3-15 4-16 4-14 3-12 3-14 3-14 4-12 4-14 5-14 5-14

Netherland 7-15 7-15 7-16 15-20 10-18 8-16 12-13 10-15 8-14 6-20

Poland 1.7 1.7 2 2 1-8 1-5 1-6 1-10 1-12 1-8 (2)

Sweeden 4-7 4-12 4-11 ? ? 2-8 2-10 3-10 3-10 5-18


Year

Plant destruction -% Effectiveness - % No of applications

C R NF R NF R NF

2003 98,5 16,5 17,5 84,3 84,3 5 3

2004 99,7

7,1

4,1 92,9 95,9 5 4

2005 99,1 18,3 14,9 81,4 84,8 7 7

2006 88,5

2007 99,5

Effectiveness of LB control – validation of Dss NegFry

(Bonin, years 2003-2007)

0,2

4,7

C – untreated control

R – routine control, aplications each 7 days

NF – applications acc. to DSS NegFry

0,2 99,8 99,8 9 6

2,3 95,3 97,7 8 5


phase of

plant

growth

Task for

protection

Choice of fungicide to control of late blight

preventive sprays

to stop/reduce

epidemics

protection of

new haulm

growth

continuation of

haulm

protection

tuber

protection


www.euroblight.net


Pathogen/ pest management strategy-3 strategy-

4. Harvesting

� maturity of tuber

� weather conditions (warm, dry), avoidance of wet loads

� avoid mechanical damages

� careful handling

5. Potato storage management

The storage period consists of three phases:

Curing - tubers have to be at a temperature of 12° to 14°C with relative

humidity above 95% for a minimum of 2 weeks for suberization of any

bruises and cuts

Holding for most of the storage time, tubers should be storage at the lowest

temperature possible without affecting market quality.

Warming, if holding temperatures were lower than 10°C, letting tubers warm

up to this temperature before removing them from storage reduces bruising.


First potato in my life

Thank you for

your attention

First potato in my life


Thank you for

your attention

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