Disease Control and Pest Management Disease Control and Pest Management in Cassava Productionin Cassava Production
International Institute of Tropical AgricultureE-mail: [email protected]; 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.