a region-wide response to emerging cassava pests and diseases in se asia

A region-wide response to emerging cassava pests and diseases in SE Asia

Kris A.G. Wyckhuys

RTB Annual Review & Planning Meeting

30/09/2014

Outline

Antecedents SE Asian cassava Plant health situation

Invasive pests & emerging diseases Cassava mealybug complex Cassava witches broom

Ongoing initiatives Monitoring Capacity building Applied research Extension

Partnerships: cornerstone of success

Cassava in SE Asia

40,000,0008,000,000

X 4

Smallholder producers

Thailand Indonesia2-3 ha/farm 0.2-0.5 ha/farm

Cambodia Laos1-4 ha/farm 0.3-0.4 ha/farm

Cassava in SE Asia

Cassava in SE Asia

Invasive pests widen yield gap

Phenacoccus manihotiCassava mealybug

First record: 2009Eastern seaboard Thailand

Host range: 9 host plant spp.Cassava, soybean, citrus

Yield impact: up to 84% lossInitial impact: 20-40% loss (2010,

Thailand)

Paracoccus marginatusPapaya mealybug

First record: 2008 – Indonesia2010 – Cambodia, Thailand

Host range: 80 host plant spp.Cassava, papaya, sweetpotato

Cassava yield impact: 40% loss(2013, India)

Ferrisia virgataStriped mealybug

First record: 1942 – Thailand

Host range: 272 plant spp.Cassava, coffee, guava, cashew,

citrus

Cassava yield impact: 20-80%(Bellotti et al., 2013)

Pseudococcus jackbeardsleyiJackbeardsleyi mealybug

First record: 1987 – Thailand

Host range: 131 plant spp.Cassava, guava, mango, cacao

Cassava yield impact: unknown

P. manihoti impact forecasts

Hyman & Herrera, unpublished

P. manihoti direct economic impact

Country Total area affected (ha)

Average 2010 yield

(t/ha)

Country-level yield loss estimates (1000 t)

Worst case (84%)

Intermediate (30%)

Thailand 246,167 18.8 3,794 1,388

Indonesia 145,556 20.2 2,411 882

India 43,600 34.8 1,244 455

Vietnam 39,503 17.3 560 205

China 4,998 16.8 69 25

Cambodia 2,843 21.0 49 18

Lao PDR 1,322 25.1 27 9

Burma 1,321 13.5 15 5

CWB: an emerging curse on cassava

Cassava witches broom

Causal pathogen 16SrI phytoplasma Presumed insect transmission Spread through infected planting material

Symptoms Stunting Leaf proliferation Yellowing / discoloration

Yield impact Average 10-15% yield losses 25-30% reduction starch content / quality Plant death General crop loss

Monitoring

Monitoring efforts

Regional scouting Vietnam/Laos/Cambodia/Myanmar/Thailand 2014 dry season ~450 cassava fields

Simple survey protocol Standardized across countries/regions Quick screening

Mealybug species complex Cassava witches broom Other phytosanitary constraints

PCR-based confirmation CWB

Anticipated outcome Early detection > Rapid response Sustained monitoring > Safe areas

Pest monitoring - 2014

Phenacoccus manihoti Paracoccus marginatus Long-tailed mealybugs

Pest monitoring - 2014

Long-tailed species

P. manihoti P. marginatus

% CM-infested plants / field

78.2 ± 26.7 4.0 ± 4.9 68.2 ± 17.5

# mealybugs / plant

36.6 ± 27.8 8.4 ± 8.2 35.7 ± 19.1

Long-tailed species

P. manihoti P. marginatus

% CM-infested plants / field

24.5 ± 19.9 35.9 ± 29.4 39.6 ± 25.5

# mealybugs / plant

2.7 ± 1.6 13.7 ± 17.0 14.8 ± 31.3

Long-tailed species

P. manihoti P. marginatus

% CM-infested plants / field

49.5 ± 28.5 16.3 ± 14.3 26.7 ± 16.1

# mealybugs / plant

9.8 ± 10.7 24.8 ± 26.5 13.6 ± 17.9

CWB monitoring - 2014

CWB monitoring - 2014

KampheangPhet 

Field-level estimate

Transect walks

% symptomatic plants

17.7 ± 17.5 6.00 ± 6.00

% fields infested

100 100

Quang Ngai 

Field-level estimate

Transect walks

% symptomatic plants

43.9 ± 24.5 39.5 ± 26.1

% fields infested

90 90

 Kracheh 

Field-level estimate

Transect walks

% symptomatic plants

44.1 ± 20.9 56.2 ± 26.9

% fields infested

100 100

Capacity building

Capacity building

Morphology-based identification

Monitoring & symptom recognition

Expert workshop & awareness-raising

Extension officer training

Applied research

Applied research – mealybug complex

CATAS - Haikou, ChinaLaboratory research

Associational resistance to P. madeirensis ~ cassava companion

crops

PPRI – Tay Ninh, VietnamField research

Mealybug – parasitoid – hyperparasitoid food webs in cassava plots of differing size

HUAF – Hue, VietnamLaboratory research

Effect of plant nutrition on P. manihoti and Anagyrus lopezi

development and fitness

KU - Bangkok, ThailandField research

Effect of mealybuginfestation level and plant age on

cassava yield

RYFCRC- Rayong, ThailandLaboratory research

Compatibility of thiamethoxam stake dips with mealybug biological

control

Applied research - CWB

HARC – Dong Nai, VietnamLaboratory research

Evaluation of dry/wet heat treatments for CWB-infested cassava planting material

PPRI – Dong Nai, VietnamField research

Membrane feeding assays to identify potential insects vectors of

CWB phytoplasma

RYFCRC – Rayong, ThailandField research

Temporal fluctuations in species composition and abundance of plant- / leafhoppers in CWB-

infested fields

Roll-out & Extension

P. manihoti invasion of Indonesia

2010 production areas

Forecasted P. manihoti impact

2010 2014

Parasitoid introduction & release

Indonesia enlists wasps in war on crop killer (ABC News)

Wasp ‘SWAT’ team to the rescue of Indonesian cassava crop (Business Insider)

Parasitic wasps unleashed on insect pest (Inside Science)

Des guêpes face aux cochenilles pour sauver le manioc (Liberation)

Farmer-to-farmer video

Mealybug prevention & control Audience

Extension workers, farmers

Farmer-to-farmer educational video Curative / preventative tactics

Healthy planting material Field sanitation & stake treatments

Translated into 7 diff. languages

Distributed through ‘agricultural cinema’ – following ‘Going Public’ methodologies

Pest/disease research network

Monitoring PPD (Vietnam), PPC, NAFRI (Laos),

GDA (Cambodia), DoA (Thailand), IPB (Indonesia)

Research PPRI, IAS, HUAF (Vietnam), Kasetsart

University, AIT & DoA (Thailand)

Extension Farmer survey work: DoAE (Thailand),

RUA (Cambodia), NUoL & PPC (Laos) Extension: PPD (Vietnam), PPC (Laos),

GDA (Cambodia), DoAE(Thailand)

Contact: Kris A.G. Wyckhuysk.wyckhuys@cgiar.org

Thanks