This document outlines initiatives to address challenges from invasive pests and diseases affecting cassava production in Southeast Asia. Monitoring efforts have found three mealybug species and cassava witches broom disease widespread across several countries. Applied research is investigating biological control of mealybugs, heat treatments for infected cassava cuttings, and potential insect vectors of the disease. Capacity building includes training local experts in identification and symptom recognition. Outreach uses videos, booklets, and other ICT tools to educate farmers on integrated pest management. The initiatives involve partnerships across multiple research and extension organizations in the region.

1. Sharing
science results:
Cassava IPM
Kris Wyckhuys
Asia Cassava Entomologist
k.wyckhuys@cgiar.org
23/06/2015
Cali, Colombia

2. Outline
 Antecedents
 SE Asian cassava
 Plant health situation
 Invasive pests & emerging diseases
 Cassava mealybug complex
 Cassava witches broom
 Ongoing initiatives – IFAD program
 Monitoring
 Applied research
 Capacity building & extension
 Partnerships: cornerstone of success

3. Invasive pests widen cassava yield gap
Asian cassava-growing areasAsian cassava-growing areas Phenacoccus manihoti
Cassava mealybug
First record: 2009
Eastern seaboard Thailand
Host range: 9 host plant spp.
Cassava, soybean, citrus
Yield impact: up to 84% loss
Initial impact: 20-40% loss
(2010, Thailand)
Phenacoccus manihoti
Cassava mealybug
First record: 2009
Eastern seaboard Thailand
Host range: 9 host plant spp.
Cassava, soybean, citrus
Yield impact: up to 84% loss
Initial impact: 20-40% loss
(2010, Thailand)
Paracoccus marginatus
Papaya mealybug
First record: 2008 – Indonesia
2010 – Cambodia, Thailand
Host range: 80 host plant spp.
Cassava, papaya, sweetpotato
Cassava yield impact: 10-40%
loss
(2013, India)
Paracoccus marginatus
Papaya mealybug
First record: 2008 – Indonesia
2010 – Cambodia, Thailand
Host range: 80 host plant spp.
Cassava, papaya, sweetpotato
Cassava yield impact: 10-40%
loss
(2013, India)
Ferrisia virgata
Striped mealybug
First record: 1942 – Thailand
Host range: 272 plant spp.
Cassava, coffee, guava,
cashew, citrus
Cassava yield impact: 20-80%
(Bellotti et al., 2013)
Ferrisia virgata
Striped mealybug
First record: 1942 – Thailand
Host range: 272 plant spp.
Cassava, coffee, guava,
cashew, citrus
Cassava yield impact: 20-80%
(Bellotti et al., 2013)
Cassava witches broom
16SrI phytoplasma
First record: 1993 – Thailand
Insect-vectored, seed-borne
Cassava yield impact: 30-35%
loss (Minato, unpublished)
Starch content: 25-30% loss
(Hoat et al., 2011)
Cassava witches broom
16SrI phytoplasma
First record: 1993 – Thailand
Insect-vectored, seed-borne
Cassava yield impact: 30-35%
loss (Minato, unpublished)
Starch content: 25-30% loss
(Hoat et al., 2011)

4. Monitoring efforts
Regional scouting
 Vietnam/Laos/Cambodia/Myanmar/Thailand
 2014 dry season: ~450 cassava fields
 2014 rainy season: ~200 fields
 Early 2015: 75 fields
Simple survey protocol
 Standardized across countries/regions
 Quick screening
 Mealybug species complex
 Cassava witches broom
 Other phytosanitary constraints
 PCR-based confirmation CWB

5. Region-wide occurrence
* Dry season data only

6. F7,1269=30.79; P<0.0001
Field-level incidence – SE
Asia
* Dry season data only

7. Mealybug distribution - 2014
Phenacoccus manihoti Paracoccus marginatus Long-tailed mealybugs

8. CWB distribution - 2014

10. CWB monitoring - 2014
Kampheang
Phet
Field-level
estimate
% symptomatic
plants
17.7 ± 17.5
% fields infested 100
Quang Ngai Field-level
estimate
%
symptomatic
plants
43.9 ± 24.5
% fields
infested
90
Cambodian cassava-growing province
Banteay
Meanchey
Pailin Battambang Kracheh Kampong
Cham
Average incidence per
field (mean ± SD)
1.20 ± 3.75 40.10 ±
34.93
31.80 ±
18.68
56.15 ±
26.94
54.10 ±
25.67
% fields with CWB 15.00 95.00 85.00 100.00 95.00

11. CWB impact on cassava yields
Minato et al., in preparation

12. Applied research – mealybug complex
PPRI – Tay Ninh, Vietnam
Field research
Mealybug – parasitoid –
hyperparasitoid food webs in
cassava plots of differing size
PPRI – Tay Ninh, Vietnam
Field research
Mealybug – parasitoid –
hyperparasitoid food webs in
cassava plots of differing size
HUAF – Hue, Vietnam
Laboratory research
Effect of plant nutrition on P.
manihoti and Anagyrus lopezi
development and fitness
HUAF – Hue, Vietnam
Laboratory research
Effect of plant nutrition on P.
manihoti and Anagyrus lopezi
development and fitness
KU - Bangkok, Thailand
Field research
Effect of mealybug
infestation level and plant
age on cassava yield
KU - Bangkok, Thailand
Field research
Effect of mealybug
infestation level and plant
age on cassava yield
RYFCRC- Rayong, Thailand
Laboratory research
Compatibility of
thiamethoxam stake dips
with mealybug biological
control
RYFCRC- Rayong, Thailand
Laboratory research
Compatibility of
thiamethoxam stake dips
with mealybug biological
control
AIT - Bangkok, Thailand
Laboratory research
Spectral reflectance and
volatile emission of cassava
under mealybug attack
AIT - Bangkok, Thailand
Laboratory research
Spectral reflectance and
volatile emission of cassava
under mealybug attack

13. Applied research - CWB
HARC – Dong Nai, Vietnam
Laboratory research
Evaluation of dry/wet heat
treatments for CWB-infested
cassava planting material
HARC – Dong Nai, Vietnam
Laboratory research
Evaluation of dry/wet heat
treatments for CWB-infested
cassava planting material
PPRI – Dong Nai, Vietnam
Field research
Membrane feeding assays to
identify potential insect
vectors of CWB phytoplasma
PPRI – Dong Nai, Vietnam
Field research
Membrane feeding assays to
identify potential insect
vectors of CWB phytoplasmaRYFCRC – Rayong, Thailand
Field research
Temporal fluctuations in
species composition and
abundance of plant- /
leafhoppers in CWB-infested
fields
RYFCRC – Rayong, Thailand
Field research
Temporal fluctuations in
species composition and
abundance of plant- /
leafhoppers in CWB-infested
fields

14. Capacity building
Morphology-based identification
Monitoring & symptom
recognition
Expert workshop & awareness-
raising
Extension officer training

15. Parasitoid introduction & release
Indonesia enlists wasps in war on crop killer (ABC News)Indonesia enlists wasps in war on crop killer (ABC News)
Wasp ‘SWAT’ team to the rescue of Indonesian cassavaWasp ‘SWAT’ team to the rescue of Indonesian cassava
crop (Business Insider)crop (Business Insider)
Parasitic wasps unleashed on insect pest (Inside Science)Parasitic wasps unleashed on insect pest (Inside Science)
Des guêpes face aux cochenilles pour sauver le maniocDes guêpes face aux cochenilles pour sauver le manioc
(Liberation)(Liberation)

16. ICT-based farmer extension
 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
 Accessible online through Youtube, CIAT
website, Access to Agriculture
 Shown through ‘agricultural cinema’ –
following ‘Going Public’ methodologies
 Active involvement of private sector in video
distribution & showings

17. CWB cartoon booklet
Neno et al., 2014

18. Nami Minato,
PhD. University
of Tokyo,
Japan
Le Ngoc Lan,
MSc. University
of Rome, Italy
Erik Delaquis, MSc.
McGill University,
Canada
Ignazio Graziosi,
PhD. University
of Kentucky, USA
Lisa Anderberg, MA.
Clark University, USA
Entom
ology
Plant pathology /
m
olecular biology
Agronom
y
Econom
ics
Rural sociology /
gender
Thort Chuong, MSc.
candidate, UC Davis,
USA
Soil science
/ m
icro-
biology
A CIAT hurricane of Energy & Talent

19. A region-wide IPM networkA region-wide IPM network
Monitoring
PPD, PPC, NAFRI, GDA, Thai
DoA, IPB, CATAS
Research
Mealybug control
PPRI, IAS, HUAF, CATAS, Thai
DoA
Monitoring & decision support
AIT, KU
Witches broom etiology &
management
PPRI, IAS, VSU
Extension
Farmer survey work
Thai DoAE, PPD, NUoL & PPC
Extension
PPD, PPC, GDA, Thai DoAE
Monitoring
PPD, PPC, NAFRI, GDA, Thai
DoA, IPB, CATAS
Research
Mealybug control
PPRI, IAS, HUAF, CATAS, Thai
DoA
Monitoring & decision support
AIT, KU
Witches broom etiology &
management
PPRI, IAS, VSU
Extension
Farmer survey work
Thai DoAE, PPD, NUoL & PPC
Extension
PPD, PPC, GDA, Thai DoAE