Bellotti, A.; Crop-insect interactions using cassava as a model

CROP-INSECT 

INTERACTIONS USING 

CASSAVA AS A MODEL: 

THE ROAD AHEAD 

Anthony C. Bellotti, , PhD. Entomologist 

Cassava Program. CIAT, Colombia

Cont… 

MAJOR ARTHROPOD PEST ASSOCIATED WITH FOUR ROOT AND 

TUBERCROPS: 

CASSAVA, POTATO, SWEET POTATO AND YAMS 

CASSAVA 

(Manihot esculenta) 

POTATO 

(Solanum tuberosum) 

SWEET POTATO 

(Ipomoea batata) 

YAM 

(Dioscorea spp.) 

Whiteflies: 

Aleurotrachelus socialis 

Bemisia tabaci 

Bemisia tuberculata 

Trialeurodes variabilis 


Trialeurodes vaporariorum 


Bemisia afer 

Mealybugs: 

Phenacoccus herreni 

Phenacoccus manihoti 

Trips: 

Franklinella williamsi 

Scyrtothrips manihoti 

Aphis: 

Myzuz persicae 

Thrips: 

Thrips palmi 

Yam mealybug: 

Pseudococcus brevipes 

Yam tuber scale: 

Aspidiella hartii 

Cocconut scale: 

Aspidiotus destructor 

Cassava hornworm: 

Erinnyis ello 

Potato tuber month: 

Pthorimaea oporculella 

Symmetrichema spp. 

Potato month: 

Tecia solanivora 

Sweet potato hornworm: 

Agrius convolvuli 

Sweet potato buttlerfly: 

Acraea acerata 

African cotton leafworm: 

Spodoptera littoralis

MAJOR ARTHROPOD PEST ASSOCIATED WITH FOUR ROOT AND TUBERCROPS: 

CASSAVA, POTATO, SWEET POTATO AND YAMS 

CASSAVA 

(Manihot esculenta) 

POTATO 

(Solanum tuberosum) 

SWEET POTATO 

(Ipomoea batata) 

YAM 

(Dioscorea spp.) 

ari: 

nonychellus tanajoa 

tranychus urticae 

Leaf minerfly: 

Liriomyza huidobrensis 

Flea beetles: 

Epitrix cucumeris 

Epitrix sp. 

Tortoise beetles: 

Aspidomorpha spp. 

Flea beetles: 

Epitrix cucumeris 

Epitrix sp. 

Systena spp. 

Grasshoppers: 

Zonozerus variegatus 

Leafcutter ant.: 

Atta sp. 

emborers: 

ilomima clarkei 

Andean weevil: 

Premnotrypes vorax 

Rhigopsidius piercei 

West indian sweet potato weevil: 

Euscepes postfasciatus 

Sweet potato weevil: 

Cylas formicarius 

C. puncticollis 

C. bruneus 

Yam tuber beetle: 

Heteroligus meles 

Whitefrienged beetle: 

Naupactus spp. 

il pest: 

rtomenus bergi 

ite grubs: 

yllophaga spp. 

Cut worm: 

Agrotis ipsilon 

Golden nematods: 

Globodera rostochiensis 

Cut worm: 

Agrotis ipsilon 

White grubs: 

Phyllophaga spp. 

Wire worms: 

Aelus sp. 

Termites: 

Amitermes evuncifer 

Cricket: 

Gymnogryllus lucens 

Garden symphylam: 

Scutigerella immaculata

YIELD LOSSES RECORDED DUE TO ARTHROPOD DAMAGE ON 

ROOT AND TUBER CROPS 

CROPS PEST AVERAGE 

LOSSSES 

Cassava 

Sweetpotato 

Potato 

Yams 

RANGE 

REGION 

White flies 

Mealybugs 

Mites 

39% 5 – 80% America / 

África 

Sweetpotato 

weevil 

Potato tuber 

month 

Termites 

Beefles 

45% 10 – 50% Cuba 

50% 11 – 65% Colombia / 

India 

35% 29 – 42% Africa

RTHROPOD PEST: INCREASED DAMAGE TO ROOT AND TUBER 

ROPS 

A. The introduction of a pest not native to an area 

B. Changes in crop management and production system (eg. Larger 

plantation size). 

C. Development of resistance in the pest to effective pesticides which 

leads to unsuccessful control 

D. Climate changes that are conducive to increased pest frequency 

and population

CLIMATE CHANGES: Arthropod Pests 

1. Altered Rainfall Patterns and Temperature Changes: 

a) Relative length of wet and dry-season 

• Lowland tropics 

• Semiarid, seasonally dry tropics 

• Subtropics 

• Highland tropics 

b) Temperature Changes: 

• Temperature is probably the single most important 

environmental factor influencing insect behavior, 

distribution, survival and reproduction- 

(Bale, et al 2002) 

c) Pest Population Dynamics

Number of consecutive dry months 

(rainfall < 100 m) 

and cassava distribution 

MITES & MEALYBUGS 

Current 

climate 

2050 

climate 

CCCMA 

a2a 

model

Number of consecutive dry months 

(rainfall < 100 mm) 

and cassava distribution 

MITES & MEALYBUGS 

Current 

climate 

2050 

climate 

CCCMA 

a2a 

model

Estimated Annual Temperature Change 

Average of 18 IPCC climate change models 

Cassava 

Potato 

Sweet potato

CLIMATE CHANGES: Arthropod Pests 

1. Effect on the Crop. 

a) More or less frequent plantings 

b) Altered planting dates 

c) Altered cropping patterns 

d) Changes in management practices 

e) Crops species selection (intercrops) 

f) Overlapping planting patterns 

g) Staggerred plantings

The effect of climate changes on arthropod pests in selected 

agroecosystems may be manifested as follows 

1. Some pest species and niches may disappear 

2. The emergence of secondary pest in higher populations and causing crop damage 

3. Change in pest distribution, an extension of geographical range 

4. Shifs in species abundance, intensification of pest management problems 

5. Changes in population growth rate, intrinsic rate of increase 

6. Increased number of pest generation during cropping cycles 

7. Extension of development season 

8. Shifts in species diversity 

9. Changes in crop-natural enemy synchrony 

10. Changes in interspecific interactions 

11. Increased risk of invasion by exotic or migrant pest 

12. Introduction of alternative host that can provide a “green bridge” between cropping 

cycles

LIFE CYCLE OF Premnotrypes vorax (ANDEAN 

POTATO WEEVIL) AT DIFFERENT ALTITUDES 

STAGE 

TIBAITATA 

(2560 MASL) 

> 16°C 

OBONUCOS 

( 2700 MASL) 

12ºC 

PARAMO DE 

LETRAS 

(3500 MASL) 

< 10ºC 

EGG 30 45 76 

LARVA 51 54 118 

PUPA 20 32 46 

ADULT PUPAL CELL 25 + 30 + 43 

TOTAL 126 151 289 

ADULT LONGEVITY (MONTH) > 12 18 ? 

Zennerde Polania, 1990

CASSAVA GREEN MITES, Mononychellus tanajoa 

TEMPERATURE 

oC 

DEVELOPMENT TIMES/DAYS 

(egg to adult) 

15 41.1 

20 19.5 

25 10.3 

30 7.8

EFFECT OF TEMEPRATURE ON THE DEVELOPMENT TIME OF THE 

CASSAVA MEALYBUG Phenacoccus herreni 

TEMEPERATURE oC 

FAMELE 

(Average Develop. Days) 

MALES 

(Average Develop. Days) 

20 90.2 51.8 

22 68.3 33.1 

25 37.6 21.9 

30 39.4 19.6 

Herrera, et al 1987)

Sao Paulo: 1900-2006 

Location: lon=-47.5, lat=-22.5 January-December 1900 – 2006 period. 

Temperature Trend = 0.21 C/decade. Significance = 100% 

Source: National Climatic Data Center 

http://www.ncdc.noaa.gov/

Effect of Climate on Crop Management (Brazil: Cassava) 

First cycle 

SOUTH BRASIL 

(RS, SC, PA,SP,MGS) 

NORTH & NORTHEAST OF BRASIL 

SEP OCT NOV DEC JAN FEB MAR APR MAY JUN JUL AGU SEP 

Planting 

Second cycle 

Harvest 

Prune 

Regrowth 

SEP OCT NOV DEC JAN FEB MAR APR MAY JUN JUL AGU SEP 

* 

P 

P 

P 

P 

H 

H 

H 

H 

egrowth & 

Planting 

Harvest 

Prune 

Regrowth 

P 

H

CASSAVA PESTS / BRAZIL / CLIMATE CHANGE 

Mites 

Whiteflies ( A. socialis) 

Mealybug (P. herreni) 

Lacebug 

Trips 

Hornworm 

Whiteflies ( B. tuberculata) 

Mealybug (P. manihoti) 

Lacebug 

Hornworm

FOUR PHASES OF IPM PROJECT 

PHASE I 

Problem and 

opportunity 

identification 

(Diagnostic) 

PHASE II 

Research & 

Tecnhology 

Development 

PHASE III 

Pilot project 

Problem identification 

Problem definition 

Definition of requirements for implementation 

Definition of research needs 

Establishment of an appropriate organozational structure 

Research (Basic + applied) 

Tecnhology development 

Reevaluation of requirement for implementation 

Evaluation by farmer 

Implementation strategy 

PHASE IV 

Implementation 

Implementation 

Adoption and impact assessment

RESEARCH & TECHNOLOGY DEVELOPMENT ROOT & 

TUBER CROPS 

Arthropod Pests 

Species 

Identification 

Geographic 

Dissemination 

Biology, Ecology 

Behavior 

Crop Damage 

Yield Loss 

Pest Management 

HPR 

Germplasm Bank 

Biological Control 

Surveys 

N.E. Selection 

Botanical Pesticides 

Cultural Control 

Agronomic Practice 

Pesticides: 

Timing/Applications 

IPM 

(Training) (FPR) (NARS)

BIOTIC STRESSES: CASSAVA 

(Arthropod Pests and Diseases) 

ASIA 

LAC 

PESTS: 

PESTS: 

Whiteflies 

Whiteflies 

Mites 

Mites 

Mealybugs 

Mealybugs 

Thrips 

Thrips 

Burrorwer bugs 

Burrorwer bugs 

Stemborers 

Stemborers 

Hornworm 

Hornworm 

Lacebugs 

Lacebugs 

DISEASES: 

DISEASES: 

Cassava Bacterial Blight (CBB) 


Cassava Root Rots 


Superelongation 

Superelongation 

Frogskin Diseases 

Frogskin Diseases 

AFRICA 

PESTS: 

PESTS: 

Whiteflies 

Whiteflies 

Mites 

Mites 

Mealybugs 

Mealybugs 

Grasshoppesr 

Grasshoppesr 

DISEASES: 

DISEASES: 

African Cassava Mosaic Diseases (CMD) 

African Cassava Mosaic Diseases (CMD) 

Cassava Brown Streak Virus (CBSV) 

Cassava Brown Streak Virus (CBSV) 





PESTS: 

PESTS: 

Whiteflies 

Whiteflies 

Mites 

Mites 

Mealybugs 

Mealybugs 

Whitegrubs 

Whitegrubs 

DISEASES: 

DISEASES: 

Root rots 

Root rots 


Cassava Bacterial Blight (CBB)

MAJOR PESTS 

Mealybugs 


Phenacoccus manihot 

Whiteflies 




B. tuberculata 

Mites 

Mononychellus tanajoa 

Mononychellus caribeanae 

Tetranychus urticae

Distribution of mealybugs asociated with cassava 

Phenacoccus madeirensis 

6 

sp. 


P. manihoti 

P. maderiensis 

P. gossipii 

Ferrisia virgata 

6 

sp. 

3 

sp.

CASSAVA MEALYBUGS 

Homoptera:Pseudococcidae 

ale 

male 


Female 

Phenacoccus manihoti

Cassava Mealybug (Phenacoccus( 

manihoti) ) Damage in Africa 

Yield Losses ~ 80%

Biological Control of the Cassava Mealybug 

(Phenacoccus manihoti) ) in Africa 

Anagyrus lopezi 

A. lopezi –Established in all 

ecological zones 

Now present in 27 countries, 

covering an area of 2.7 million 

Km 

Cassava losses reduced by 

90-95% 

Estimated saving US$7.97 to 

20.23 billion

Yield Losses > 80%

Introduced 

Anagyrus diversicornis 

Aenasius vexans 

INTRODUCED 

Acerophagus coccois 

Introduced into Brasil 

and released (1994- 

1996) CIAT/EMBRAPA

ASIA/TAILAND 

1975 

Geographic distribution of cassa 

mealybugs in Brazil 

Origin of Phenacoccus herreni, 

Colombia, Venezuela 

1980 

2005 

Introduction 

A. lopezi 

P. herreni 

P. manihoti 

Anagyrus lopezi

CASSAVA MEALYBUG AND DAMAGE: TAILANDIA 


Phenacoccus madeirensis 

PARASITOIDES: 

Anagyrus diversicornis 

Acerophagus coccois 

Aenasius vexans

Distribution of Phytophagous mites associated with 

cassava 

Oligonichus biharensis 

Tetranychus kansawai 

T. truncatus 

T. neocaledonucus 

Eutetranychus orientalis 

Tetranychus urticae 

Tetranychus marianae 


Tetranychus urticae 

T. neocaledonicus


Cassava Green Mite 

ield Losses: Americas 21 – 73% 

Africa 13 – 80%

Distribution of Mononychellus tanajoa asociated 

with cassava 

~ 1970

MANAGEMENT OF CASSAVA MITES 

HOST PLANT RESISTANCE 

BIOLOGICAL CONTROL

EVALUATION OF CASSAVA GERMPLASM FOR 

RESISTANCE TO THE CGM, Mononychellus tanajoa 

DAMAGE SCALE 

No. VARIETIES 

1.0 

2.0 

3.0 

4.0 

5.0 

6.0 

0 

48 

348 

2442 

755 

1047 

8.53% 

TOTAL 4640 

1.0 >> High level of resistance 

2.0 >> Moderate level of resistance 

3.0 >> Low level of resistance 

4.0 – 6.0 >> Susceptible

CASSAVA GREEN MITES ON 

RESISTANT CLONES HAVE: 

Nataima 31 

ICA Costeña (NG-1141-3 

1. Lower fecundity 

2. Longer development times 

3. Shorter adult life spans 

4. Higher adult and nymphal mortality 

5. Lower reproductive rates 

Than mites on susceptible clones

Biological Control of the Cassava Green Mite 

a Project of International Collaboration 

Quarantine 

QMP 

CIAT 

Quarantine 

& 

Introduction 

EMBRAPA 

CNPMF 

IITA 

Introduction 

Distribution

Phytoseiidae: Predaceous Mites

12 

Yield (Ton/ha) 

11 

10 

35% Yield loss 

9 

8 

Predators eliminated No Pesticide Pesticides spray Mites 

eliminated

Biological Control of Cassava 

Mites 

Countries Surveyed 17 

Sampling Sites 2500 

Species Collected from Cassava 66 

New (Unrecorded) Species 26 

Phytoseiid Population Studied 114 

Taxonomic Key Developed 53

N. idaeus T. manihoti T. aripo 

LEASED (1st) 

untries Where 

ished 

sion Rate 

ar) 

1989 1989 1993 

2 4 15 

0.01 2.5 12.5 

overed (Km²) < 10 1.300 400.000 

tion in CGM Population 0% 50% 30 - 90% 

Root yield incresae: 30-70% (Onzo, et al 2005) 

IITA/BENIN

CGM Populations reduced by 30 -90% 

Root yield increase: 30-70% 

(Onzo et al, 2005)

Global Distribution of Phytoseiids mites associated 

with phytophagous mites in cassava 

Neoseiulus longispinosus 

Amblyseius aerialis 

Neoseiulus anonymus 

Neoaseiulus idaeus 

Neoseiulus californicus 

Typhlodromalus limonicus 

Typhlodromalus aripo 

Typhlodromalus manihoti 

Galendromus annectens 

Galendromus helveolus 

> 40 species 

Amblyseius largoensis 

A.tamatavensis 

Euseius fustis 

E. papayana 

Euseius spp 

Iphiseius degenerans 

Neoseiulus teke 

Neoseiulus spp 

Paraphytoseius multidentatus 

Typhlodromalus saltus 

Typhlodromips rykei 

Phytoseius amba 

Amblyseus arialis 

Neseiulus anonymus 

N. idaeus 

Typhlodromalus limonicus 

Galendromus annectens 

G. helveolus

cional de Agricultura Tropical 

enter for Tropical Agriculture 

TETRANYCHUS MITES AND DAMAGE 

Potential Phytoseiids 

Amblyseius aerialis 

Phytoseiulus macropilis 

Neoseiulus anonymus 

Neoseiulus idaeus 

Typhlodromalus aripo 

Population 

Damage

Diagnostic 

Basic Reaserch 

Host plant Resistance 

Biological Control 

Chemical Control 

Training 

Tropical Whitefly IPM Project (SPIPM)

Global Distribution of Cassava Whiteflies 


Bemisia tuberculata 

Bemisia afer 


Aleurothrixus aepim 


Aleurodicus dispersis

Importance of Cassava Pests in Colombia: Departament of Risaralda, 

a, 

Quindio & Caldas 

100 

FREQUENCY 

90 

80 

70 

60 

50 

40 

30 

75,58 

32,25 

32,25 

22,58 

Yield reduction in 

farmer trials: 58% 

20 

10 

1,61 

9,67 

14,51 

4,83 4,83 

0 

Whitefly Shootflies Mite Hornworm Whitegrubs Thrips Burrower 

bugs 

18% 

PESTS 

52% 

Leafcutter 

ants 

No 

34% 

82% 

KNOWLEDGE 

NO KNOWLEDGE 

CHEMICAL BIOLOGICAL NON CONVENTIONAL NO CONTROL 

LACK OF KNOWLEDGE OF PEST CONTROL PRACTICES USED BY FARMER 

9% 

5%

WHITEFLIES 

High whitefly populations occur during rainy periods when 

there is considerable leaf and plant growth 

Whitefly populations can double every 4.1 days 

Yield losses from 40% to 79% recorded in field trials

Pesticides cause 

a disequilibria 

Disruption of biological control of 

Whiteflies and other pest (Mites, 

Mealybugs) 

Increased resistance of pests to 

pesticides 

Host plant resistance is 

the most economic 

solution for control of 

cassava whiteflies

DEVELOPING PLANTS RESISTANT TO 

ARTHROPOD PESTS 

Germplasm Bank: ample genetic diversity 

Methodology for mass rearing pest 

Methodology to distinguish resistant and susceptible 

germplasm 

Ample natural field populations of pest to permit selection 

pressure 

Breeding scheme to incorporate resistance into 

commercial cultivars

Mass rearing and germplasm evaluation

Nonadapted source 

of resistance 

x 

Agronomically desirable 

Susceptible clones 

Evaluation of progeny for agronomic desirability plus resistance 

Crossing again to resistance source 

NO 

Resistance levels adequate 

Recurrent selection 

YES 

Crossing again to good 

agronomic source 

NO 

Agronomic performance adequate 

Release cultivar 

YES

Cassava Germplasm Evaluated for Whitefly (Aleurotrachelus 

socialis) ) Resistance 

(Total GB 5406 Accessions) 

Evaluation Sites 

Departments 

Valle del Cauca 

(CEUNP-Palmira Palmira and Jamundí) 

Cauca 

(Santander de Quilichao) 

Tolima 

(Espinal-CORPOICA) 

Atlantic Coast 

Atlántico (4 Locations), 

Bolívar (1), Sucre (3), 

Córdoba (1) 

5363 Genotypes Evaluated 

367 Promising 

13 Locations 

40 Selected

MEcu 72 

70% Mortality of Nymphal Instars

Whiteflies Host Plant Resistance 

Whiteflies Host Plant Resistance 

Aleurotrachelus socialis feeding on Resistance 

Genotypes have: 

Less oviposition 

ANTIXENOSIS 

Reduced size 

Longer development time ANTIBIOSIS 

Higher mortality 

Than those feeding on susceptible genotypes 

Results in 

Slower reproduction rate 

Reduce population build-up

Developing a Whitefly Resistant Commercial 

Cassava Cultivar 

Parents: 

MEcu 72(R) x MBra 12 (T) 

Progeny (127), Selected: 

GC 489-4 

CG 489-31 

CG 489-34 

CG 489-23 

Susceptible Controls: 

CMC 40 

H 305-122 

MCol 1505(T?) 

Farmers Cultivars: 

Aroma 

Quindío

YIELD OF 6 CASSAVA GENOTYPES EVALUATED UNDER WHITEFLY 

(Aleurotrachelus socialis) ) PRESSURE AT CORPOICA, 

NATAIMA (B), EL ESPINAL, TOLIMA 

35 

30 

YIELD (T/ha) 

25 

20 

15 

10 

5 

0 

CG 489-31 CG 489-34 CG 489-23 CG 489-4 CMC 40 Aroma 

CG 489-31 

Genotypes 

Ecu 72 x MBra 12 

Farmer cultivar

RELEASE OF NATAIMA-31 

Colombia, MADR, 2003

Cassava Cultivars and Hybrids Resistant 

to Whiteflies 

(A. socialis) 

Nataima 31 

MEcu 72 

MEcu 64 

MPer 334 

MPer 415 

MPer 273 

MPer 611 

MPer 317 

MPer 216 

MBra 292 

CG 489-34 

CG 489-23 

CG 489-31 

CG 489-4 

CM 8424-6 

CM 8424-33 

CM 8424-2 

uced into Africa (Uganda): Resistance to B. tabaci

BIOLOGICAL CONTROL 

Percent mortality of A. socialis nynphs infected with different 

entomopathogens (Isolates) 

Lecanicillium lecanii 

% Mortality 

80 

70 

60 

50 

40 

30 

20 

36.7 33.3 

44.4 

* 

65.4 

* 

36.8 

Paecilomyces fumosoroseus 

* 

47.1 

Beauveria bassiana 

15 16.8 

10 

0 

Isolate 

CIAT 210 CIAT 211 CIAT 212 CIAT 215 CIAT 216 CIAT 217 Control 1 Control 2 

* Collected from A. socialis

FUNGAL 

ENTOMOPATHOGENS 

(Lecanicillium lecanni) 

Cepa CIAT 215 

PRODUCTO COMERCIAL 

BioCanii® 

(BIOTROPICAL S.A.) 

PRODUCTO 

COMERCIAL Vercani® 

(SAFER) 

Lecanicillium lecanii on development Stages of A. socialis 

07

CHEMICAL CONTROL 

Stake treatment - Immersion 

in a solution of 

Thiamethoxam (Actara®) 

Foliar application 

APPLY TO LOWER LEAF SURFACE

ACTION THRESHOLD 

ge 

) 

16 

14 

12 

10 

8 

6 

4 

2 

0 

Economic threshold 

Economic damage 

10 20 30 40 50 60 70 80 

Population 

(P) 

Initiate control 

Initiate control 

Biological application: 

Adult-Egg: 1 – 50 

Nynph – Pupae: 1 - 200 

Chemical application: 

Adult-Egg: 51 - 200 

Nynph – Pupae: 201 - 500

Yield (t/ha) 

30 

20 

Cassava yields (t/ha) of seven treatments for Whitefly 

Control. 

(Calarca, Quindio, Col., 2008) 

Stake treatment 

Population monitor 

Foliar application – Chemical. (2) 

Foliar application - Biological (1) 

10 

Neem 

Extract 

Integrated 

Control 

Enthomophthora 

Extract 

L. lecanii B. bassiana Garlic/chili 

Extract 

control 

Treatments 

Control applications needs only during first 6 months of crop cycle

African Cassava Mosaic Disease 

isia tabaci 

ACMD: Not prese 

in the Americas a 

most of Asia (Indi

Bemisia tabaci (Biotype B) Survival on Manihot esculenta (Cassava) and 

M. carthaginensis when Populations Originate from Three Alternate Hosts 

2% 

Phaseolus vulgaris 

3% 

Euphorbia pulcherrima 

27.5% 60% 

Jatropha gossypiifolia 

M. esculenta M. carthaginensis



QUARENTINE 

MOVEMENT OF CASSAVA PESTS FROM INFESTED TO NON- 

INFESTED AREAS 

EM CUTTINGS 

Mites 

Mealybugs 

Thrips 

Stemborers 

Scales 

Shoot flies 

FOLIAGE / PLANTS 

• Whiteflies 

• Hornworm 

• Lacebugs 

FRUIT 

• Fruitflies



QUARENTINE RECOMMENDATIONS: 

GENERAL 

Material should be collected, processed and shipped with the necessary 

precautions to avoid accidental movement of pest 

Under no circumstances should germplasm be moved as rooted plant 

material except for in vitro plantlets 

Cassava germplasm can be moved as seed, pathogen-test in vitro material, 

or as cuttings from re-established pathogen-tested in vitro material that has 

been grown under containment. 

Only under special circumstances should the movement of untested, 

vegetative material be considered 

All germplasm should be collected from healthy-looking plants and when 

possible from areas where quarantine pests are not present. 

Germplasm from areas where pest of quarantine concern are known to occur 

should go through intermediate, or post-entry quarantine 

The transfer of germplasm should be carefully planned in consultation with 

quarantine authorities and should be in amounts that allow adequate 

handling and examination. The material should be accompanied with the 

necessary documentation.

Identification and Genetic Mapping of Host Plant 

Resistance to Whiteflies and Green Mites in Wild 

relatives of Cassava 

ACCESSIONS OF M. 

flabellifolia 

T: 833 ACCESSIONS OF 33 WILD SPECIES 

source for resistance or tolerance to biotic and abiotic stresse

Average Damage Rating 

6 

5 

4 

3 

2 

1 

0 

5 15 25 35 45 55 

Days after infestation 

MFLA 444- 

002 

ECU 72 

CMC 40 

MPER 417- 

003 

MPER 417- 

005

Oviposition curves of Aleurtrachelus socialis on accessions of 

Manihot flabellifolia and susceptible (CMC-40) and resistant 

(Mecu-72) cassava genotipes 

Eggs/females/2 

days 

40 

35 

30 

25 

20 

15 

10 

M fla61 

M fla52 

M fla19 

M fla33 

M fla25 

M fla21 

M fla15 

M fla75 

C M C 40 

M Ecu72 

5 

0 

0 2 4 6 8 10 12 14 16 18 20 22 24 26 28 30 32 34 

Age of females (days) 

Age of females (days)

Survival curves of Aleurotrachelus socialis famales on accesions 

of Manihot flabellifolia and susceptible (CMC-40) and resistant 

(Mecu-72) cassava genotipes 

Proportion of live 

female 

1 

0.9 

0.8 

0.7 

0.6 

0.5 

0.4 

0.3 

0.2 

Mfla61 

Mfla52 

Mfla19 

Mfla33 

Mfla25 

Mfla21 

Mfla15 

Mfla75 

CMC40 

MEcu72 

0.1 

0 

0 2 4 6 8 10 12 14 16 18 20 22 24 26 28 30 32 34 36 

Days after infestation

Summary of Genetic Mapping for 

Whiteflies 

Over 500 SSR markers scored in bulk segregant analysis (BSA) 

About 7 markers found to be associated with resistance 

Putative markers associated with resistance to whiteflies are being tested 

GENOTIPO 

FLA 347-007 

MTAI 8 

76-1 

76-7 

80-1 

81-2 

220-9 

224-6 

225-6 

226-10 

229-7 

231-19 

235-10 

236-15 

236-16 

236-17 

242-2 

248-2 

259-40 

260-5 

76-2 

214-3 

214-9 

217-7 

219-3 

229-3 

229-12 

231-2 

232-2 

232-5 

232-8 

235-3 

235-5 

235-8 

235-21 

235-25 

235-94 

235-95 

OTIPO 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 5 5 5 5 5 5 5 5 5 5 5 5 5 5 5 5 5 5 

Y 346

Development of Genetic markers for 

Resistance to Cassava Green Mites from M. 

esculenta sub spp flabelllifolia

Moderate Levels of Green Mites (M.tanajoa) Resistance have 

been found in BC 1 derivatives of some accessions of 

M.esculenta sub spp flabellifolia 

7 

6 

5 

MFLA 444-002 

ECU 72 

Average Damage Rating 

4 

3 

2 

1 

CMC 40 

MPER 417-003 

MPER 417-005 

0 

10 15 20 25 

Days of infestation

Genotyping and Phenotyping of BC 1 Mapping 

Populations for Resistance to Green Mites 

Summary of Genetic mapping for Green Mites 

Over 600 SSR markers scored in bulk segregant analysis (BSA) 

About 7 markers found to be associated with resistance 

Two markers confirmed to be associated with resistance to CGM 

Resistance Bulk Susceptible Bulk 

SSRY 11

18 

Oviposition (# eggs/female/3 days) on Mononychellus 

tanajoa on different genotypes of Wild Manihot species 

(30 repetitions) 

15 

Average # eggs 

12 

9 

6 

3 

0 

CM C 40 M . violacea 1 M . flabellifolia 

75 

M .brachyloba M . alutacea 4 M . filamentosa 

3 

M . tristi 8 

Genotypes

Important criteria and future trends in 

management of arthropod pests 

Greater yield losses on larger plantations. 

Changing climatic patterns will influence pest occurrence and population dynamic. 

Increased pesticide use in relation to larger plantations and industrial production. 

Disruption of natural biological control. 

Continual or overlapping production cycles: 

Increased pest incidence and population 

Numerous pesticide applications 

Development of biological and botanical pesticides: 

Fungal entomopathogens, baculoviruses 

Neem 

High cost of production 

Host plant resistance most practical and cost efficient for small and large producers. 

Increased research emphasis on wild Manihot species as source of resistance to major pests. 

Quarentine regulations

“ECOLOGY like Genetics, 

is not about Equilibrium States. 

It is about change, change, change. 

Nothing stays the same forever.” 

Genome: M. Ridley, 2002

Bellotti, A.; Crop-insect interactions using cassava as a model

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