Disease Control and Pest Management Disease Control and Pest Management in Cassava Productionin Cassava Production

International Institute of Tropical AgricultureE-mail: L.kumar@cgiar.org; www.iita.org

Lava Kumar, R. Hanna, P. Kulakow, J. Legg, E. Kanju, P. Ntuhunguru and N. Mahungu

IntroductionNeed for cassava intensification• To meet the demands of increasing population growth• Increase in demand for alternative uses - bioenergy

Way forward• Increase in yields in the same unit area in traditional growing

areas• Cultivation in new nichesChallenges• Poor adoption of improved varieties and crop management

practices.• Threats from established and emerging pests and diseases

in traditional and new cassava niches. • Climate change effect on host, pathogens and pests.• Lack of enabling environment (inadequate financial, policy

and political support)

Cassava productivity

EA = 8.8 MtCA =8.9 mt

NA=1.6 MtWA=11.5 mt

CA=11.9 mt

SA=13.5 mt

SA=32.5 mt

EA=16.6 mt

SEA=19.3 mt

Latin America•Traditional cultivation•Pests and diseases

Asia•Adoption of improved varieties and technologies from the outset•Low pests and diseases

Africa•Subsistence agriculture•Poor adoption of improved varieties •Diseases (CMD & CBSD) and pests

Cassava yield

Genotype

Environment Management

Biotic stresses

Abiotic stresses

GEM factor on cassava yield

Pests Diseases

Planting material

Exotic pests• Green spider mite (Mononychellus tanajoa) • Cassava mealy bug, (Phenacoccus manihoti) • Cassava Bacterial Blight (Xanthomonas axonopodis) • Indian cassava mosaic virus

Pests of regional importance1. Cassava brown streak virus2. East African cassava mosaic virus – Uganda (EACMV-

UG)

Cassava pests in AfricaIndigenous pests1. African cassava mosaic virus2. East African cassava mosaic virus complex3. South African cassava mosaic virus4. Whiteflies, fungal diseases, root scales etc

Pests not present in the continent1. Cassava common mosaic virus2. Cassava green mosaic virus 3. Cassava vein virus 4. Cassava X virus5. Frog Skin Disease 6. Cassava antholysis 7. Cassava witches broom8. Super Elongation (Sphaceloma manihoticola)

Quarantine pests of cassava in Africa

Cassava die-back caused by Collectotricum gloeosporioides

Leaf spots caused by Collectotricum gloeosporioides

Cassava bacterial blight (CBB) Xanthomonas axonopodis pv manihotis

Leaf spots caused by Cercospora caribea

Brown leaf spot Cercospora henigsiiSuper Elongation

(Sphaceloma manihoticola- Elsinoe brasilensis)

Source: E. Alvarez, PD 87

Severe mottling and leaf distortion on indicator clone Secundina grafted on infected stake (leaves from buds on rootstock show no symptoms) Source: Dr L.A. Calvert, CIAT

Frog skin disease (FSD)

Cassava green mite (Mononychellus tanajoa)

Predatory mite -- Typhlodromalus aripo feeds on cassava green mite

Introduced to Africa from Brazil in 1993 for biological control of cassava green mite Mononychellus tanajoa

and biocontrol

Whitefly (Bemisica tabaci)

Pest and important virus vector

Sooty mould

The viruses of cassava in AfricaAfrican cassava mosaic virus (ACMV) Indian cassava mosaic virus

East African cassava mosaic virus (EACMV)South African cassava mosaic virus (SACMV) East African cassava mosaic Cameroon virus East African cassava mosaic Malawi virusEast African cassava mosaic Zanzibar virus East African cassava mosaic Kenya virus EACMV-Uganda (recombinant virus)

Cassava brown streak virus (Ipomovirus)Cassava brown streak Uganda virus

Cassava Ivorian bacilliform virus* Cassava Kumi virus*Cassava ‘Q’ virus*Cassava common mosaic virus* (Potexvirus)

CMGsCMGs

CBSVCBSV

ACMV only ACMV+EACMV

ACMV+EACMV ACMV+EACMV

Movement of CMBV’s in SSA

Source: Ndunguru et al. 2005

Viruses cannot move, they are moved

•They move with host (propagation material)

•They are transmitted by vectors

Cassava virus spread

Whiteflies Stem cuttings In vitro cultures

CMG Distribution - 2004

CMG Distribution

01020304050607080

Nigeria

Ghana

08

Ghana

89

Camero

on08

-09

Cote d'

Ivorie

-09

Benin

07-08

Sierra

Leon

e 09

Angola

08

ACMVBothNoneEACMVUgV%

inci

denc

e

• Increase in incidence of mixed infections in West Central Africa

Tracking the spread of EACMV-UG

•As of 2005, Spread in 2.6 million sq. km causing an estimated loss of 47% in affected countries.

2009

2008

2009

•Spread into Cameroon in West-Central Africa •Spread into Angola in Southern Africa•Also reported from Burkina Faso and Togo in 2009

Farmer yields of improved and local varieties by state in SS and SE Nigeria

CMD decreased by 30.8%

y = -0.0044x + 9.1817R2 = 0.1741

0.25

0.30

0.35

0.40

0.45

0.50

0.55

0.60

0.65

0.70

1970 1975 1980 1985 1990 1995 2000

Cassava Mosaic Disease Severity

Year of cloning

Mea

n lo

g(C

MD

sev

erity

)

Genetic gain/year = 0.44%

*Better management of cassava mosaic disease

Production (Million Mt)

Value (million US$)

15% increase*

(million Mt)

Additional value

(million US$)Nigeria 45.72 3200.5 6.86 480.1DRC 14.97 1048.2 2.25 157.2Ghana 9.64 674.7 1.45 101.2

Benin 2.52 176.7 0.38 26.5Ivory Coast 2.20 154.0 0.33 23.1

Total 76.06 5324.0 11.41 798.61

•Additional production of 11.4 million tons•Additional value of US$ 798.6 millions

Cassava brown streak virus

• First recognized in 1920s.• Occurs in Kenya, Uganda, Tanzania,

Malawi and Mozambique.• Suspected in DRC, Congo, Burundi

and Rwanda. Evidence of westward spread

Prior to 2005

Post 2005

Cassava brown streak disease

DRC

Kenya

Tanzania

Mozambique

ZambiaMalawi

RwandaBurundi

UgandaCBSD incidenceNot surveyedNo CBSD> 0 - 3 %3 - 10 %> 10 %

C3P Project

New R

epor

ts

Post

-200

4

Reports prior to 2004

(since 1920s)

CBSD distribution

•Tracking CBSD distribution and spread

•Since 2008, its occurrence in Rwanda, Burundi and Eastern DRC confirmed.

CBSD

CBSD disguise ready detection

Near normal tubers, but server damage to root quality

FN434109 CBSV-Ug 23 (full sequence) 2...

EU916829 CBSV (LWR2) CP

EU916828 CBSV (HMA9) CP

EU916830 CBSV (IGA8) CP

EU916827 CBSV (NTG10) CP

EU916832 CBSV (BSA4) CP

EU916831 CBSV (BSA2) CP

FN433930 CBSV Kenya 125 1999 (Kenya:K...

FN433932 CBSV-Ma 42 2007 (Malawi:Chit...

FN433933 CBSV Ma 43 2007 (Malawi:Salima)

FN433931 CBSV-Ke 54 1997 (Kenya:Kilifi)

EU916826 CBSV (MLB9) CP

NC 012698 CBSV isolate MLB3 full geno...

EU916825 CBSV (MLB3) CP

FN434436 CBSV-Mo 83 (full sequence) 2...

GQ329864 CBSV-Tz (full sequence) 200...

FN434437 CBSV-Tan 70 (full sequence) ...

AY008440 CBSV (type C) CP

AY007597 CBSV CP

AY008441 CBSV (type B) CP

FJ821795 CBSV (KBH1) CP

FJ821794 CBSV (KBH2) CP

AY008442 CBSV (type A) CP

AF311053 CBSV

AF311052 CBSV98

92

99

80

89

57

30

27

19

10099

100

6397

84

97

57

55

100

3627

11

0.05

CBSV

CBSUV

Two viruses

Difficult to diagnose CBSD

Cassava brown streak disease

CMD CBSD CMD+CBSD

Simple diagnostics developed at IITA for simultaneous diagnosis of CMD and CBSD

Lanes 1 to 4: CBSV infected samplesLane 5: Healthy cassavaLane 6: CMD infected cassavaLane M: Molecular weight marker (100 kb ladder)

M 1 2 3 4 5 6 7 1 2 3 4 5 6 7 M 1 2 3 4 5 6 7 1 2 3 4 5 6 7 M

CBSV-S1/S2 + CMB CBSV-L1/L2 + CMB

Sap DNA & RNA Sap DNA&RNA

EACMV

ACMV

CBSV

Districts

0

10

20

30

40

50

60

70

80

90

Thyolo

Mulanje

Chirad

zulo

Zomba

Salima

Nkhota

Kota

Nkhata

Bay

Rumph

i

Karong

a

Chitipa

Mzimba

Kasun

gu

Total samplesSymptomatic samples

Total positive in RT-PCR

Positive with CBSV-F3/R3 primers

Positive with CBSV-10/11 primers

Num

ber

Districts

0

10

20

30

40

50

60

70

80

90

Thyolo

Mulanje

Chirad

zulo

Zomba

Salima

Nkhota

Kota

Nkhata

Bay

Rumph

i

Karong

a

Chitipa

Mzimba

Kasun

gu

Total samplesSymptomatic samples

Total positive in RT-PCR

Positive with CBSV-F3/R3 primers

Positive with CBSV-10/11 primers

Num

ber

USAID project

CBSD management •Cultivation of tolerant varieties

•Clean planting material

•CBSD is a serious threat to cassava worldwide.

•Consorted efforts are required to pre-emptive management of CBSD

Spiraling whitefly (Aleurodicus dispersus)

Watch-out for new pests

•Cassava mealybug (Phenococcus manihoti) well established in Latin America and SSA.

•New outbreak in 200,000 ha in Thai Land (CIAT Alert, 2010)

•Threat to other Asian countries.

Watch-out for new outbreaks

Source: www.cgiar.org

Anagyrus lopezi

Biological control using natural enemy, a wasp, A. lopezi.

•Cassava bacterial blight in Vietnam.

•New Phytoplasma disease in South-East Asia

Watch-out for new outbreaks

Source: www.cgiar.org

•Training in field surveillance and laboratory diagnosis

Training & capacity building

Awareness creation

Planting material Tubers Starch Ethanol

Poor quality No managemen

tPoor yield

CropManagement Increase in yield Good quality

Quality planting material is fundamental to increase cassava productivity

Quality planting material to manage biotic threats

Challenges due to clonal propagation

• Very low multiplication ratio (1:8), bulky & Perishable• Multiplication and distribution of stems are more

expensive than conventional seed (grain based)• Farmers do not specifically multiply stems for propagation,

but use stems from harvested plants. • Lack of incentive for the private sector to invest, and lack of

markets (due to low affordability by farmers)

Challenges due to clonal propagation (2)

• Spread of pathogens particularly viruses (introduction and perpetuation)

cutting from virus infected cassava

Infected cassava Healthy cassava

Infected cassava

Direct spread

Indirect spread

WhitefliesVectors

Stems

Few actors involved in cassava stem multiplication

• Private non-profit organizations (e.g. NGOs, foundations);

• Public institutions (e.g. extension services, research institutions)

• Community organizations (CBOs)

• Depends on donor investments• Lack of sustainability• Cultural issues sometimes affect

multiplication projects

•Weak seed sector, •Expansion of area (intensification)

•High demand for planting material•Short supply of planting material

Massive multiplication & exchange programs

•Demand met through massive multiplication projects

•Massive movement of planting material within & between countries

•Inherent risk of pathogen exchange through planting material

•Particular problem with viruses - Cassava mosaic disease - Cassava brown streak disease

•Planting material could carry pathogens harmful pests and pathogens.

Knowledge on pathogens and their distribution

Essential needs for germplasm monitoring

Availability of diagnostic tools

Capacity (human skills and infrastructure)Fund

s

Guidelines: FAO, IPPC, IAPSC, NPPO

Production of clean planting material

Material from the field:•Insects •Nematodes•Fungi•Bacteria •Viruses

•Elimination of pests and pathogens through tissue culture, but not viruses.

Variety

No. of tested

Number CBSV-free

1 MM06/0011 20TC 15 2 MM06/0024 20TC 10 3 MM06/0138 20TC 3 4 MM06/0131 20TC 3 5 MM06/0019 20TC 9 6 MM06/0079 20TC 11 7 MM06/0013 20TC 1 8 MM06/0045 20TC 20 9 MM06/0012 20TC 20

10 MM06/0023B 20TC 8 11 MM06/0139 20TC 2 12 MM06/0124 20TC 4 13 MM06/0112 20TC 3 14 MM06/0076 20TC 6

Scheme for CBSD-free planting material

•Provide adequate supply of cassava products at economically affordable prices through availability of improved cassava varieties, production processes and farm gate processing in seven countries.

•Together with national programs and CSOs

Unleashing the Power of Cassava in Africa – UPoCA(USDA project in response to food crisis)

•To distribute clean planting material to 1.15 million households in 6 countries.

•To strengthen the capacity of local partners to address CMD and CBSD threat to food security and income of cassava-depending farm families.

•8 national programs, 2 IARCs, 53 CSOs; 3,000 farmer groups.

Great Lakes Cassava Initiative – GLCI (1)(CRS-led BMGF project)

Great Lakes Cassava Initiative – GLCI (2)(CRS-led BMGF project)

Research activities (IITA led-component)-Studies on CMD and CBSD-Improve disease control through better varieties and planting material quality management

Development activities -Multiplication & dissemination of clean seeds (planting material)-Farmer group development-Partner capacity building

•Tanzania is amongst the worst hit by CBSD and CMD.

•Source of planting material for ambitious biofuel production in Tanzania?

©IITA©IITA

Sourcing quality planting material is the major challenge to biofuel production in Africa

Individual farmers, farmer groups

Tertiary multipliers

1-2ha/site

2ha/site

NGO’s, farmer groups

Secondary multipliers

Primary multipliers

Research stations, NGO’s

10ha Foundation stockResearch stations

Sustainable production of quality

planting material

Need for sustainable clean seed systems

Viral diseasesCMD, CBSD

•CMD resistant varieties •Tolerance to CBSD•Planting material •Quarantine monitoring

•New resistant varieties•Novel approaches for insect control

•Adoption of technologies•Capacity building & stretching of monitoring programs

•Investment in research & development

Fungal & bacterial diseasesCBB, anthracnose, super elongation

•Crop management•Resistant varieties •Planting material •Quarantine monitoring

Insect pestsMealybugs, mites, whitefly, root scales

•Crop management•Resistant varieties •Planting material •Quarantine monitoring

Diseases of uncertain etiologyFrog skin disease

•Crop management•Planting material •Quarantine monitoring

Summary & Conclusion

Interest in biofuel can transform cassava potential in Africa.

IITA Campus - Ibadan

Thanks for your attention

L.kumar@cgiar.orgwww.iita.org