Successful strategies against bacterial wilt in SSA

Dr. Ir. Dieudonné HarahagazweInternational Potato Center, CIP

CONTROL OF BACTERIAL WILT IN EASTERN,

CENTRAL AND SOUTHERN AFRICA:

Successful Strategies

Bacterial Wilt in SSA

= Ennemy No. 1 of Seed Production

Systems

Reduction of field BW infection from 60% to

0.7% (Berrios and Rubirigi, 1993)

Disease Triangle = Basis of Control Strategies

Pathogen

Host

Environment

Strategy 1

Clean Seed

• Formal Seed Systems

• Informal Seed Systems

Formal Seed Production Systems

• In vitro plantlet multiplication

• Mini-tuber production

– Conventional technique (sterilized substrate)

– Rapid multiplication techniques (cuttings)

– Aeroponic technique (Kenya, Malawi,

Mozambique, Rwanda)

– Sand hydroponic (Tanzania, Mozambique,

Rwanda)

• Field Multiplication:

– Pre-basic Seed Production

– Basic Seed Production

– Certified Seed Production

• Case Study: Burundi Seed Scheme

Tissue Culture Labs

Lichinga, Mozambique (2012) Ruhengeri, Rwanda (2006)

Tigoni, Kenya (2011)

Gisozi, Burundi (2012)

Conventional mini tuber

production

Ruhengeri, Rwanda (2006) Mulungu, DR Congo (2013)

Sterilization of SubstrateRuhengeri, Rwanda (2006)


Sussundenga, Mozambique (2013)

Aeroponic Seed Production

Tigoni, Kenya (2010)

Malawi, 2010

Sand Hydroponic Production

Maputo, Mozambique (2013)

Source: Armando Chilenge

Cold storage (Lichinga, Mozambique)

Quality Assurance and Control

�Official Standards

(variability across countries)

�Field Inspection

�Lab techniques

(Latent infection mainly)


Informal Seed Production

Self Supply of Clean Seed by

small-scale farmers:

–Small plot techniques

–Diffused Light Storage (DLS)

Small Plot Technique

• Gusubizako ivu

• Gutera: 20 cm x 20 cm

• Gukangaza no gufurira

• Gupompa

• Gusoroma

1,6 m

9

m

Buyengero, Burundi (2007)

Buyengero, Burundi (2007)

Season 1

Season 2

Season 3

Season 4

SSP 1

SSP 2

SSP 3

SSP 4

Ware Plot 1

Ware Plot 2

Ware Plot 3

Market

Market

Market

Sequence of Seed and ware Plots

Quality Seed Means Approriate Storage

Angonia, Mozambique (2012) Tsangano, Mozambique (2010)

Promotion of low cost DLS for farmers

Farmers’ DLS at Malomo EPA in Ntchisi (Nov. 2009)

Farmers’ DLS in Mchinji (Nov. 2009)

A farmer inside his DLS in Mchinji, 2011

Examples of DLS in Malawi (Source:

P. Demo)

Farmer’s Improved DLS

Rotanda, Mozambique (2012)

Strategy 2

Pathogen Free Land/Soil

Example of

• Western Kenya

• Central Kenya

• Mozambique

Bacterial Wilt Incidence in Western Kenya (Trials 2013)

Genotype

3930

79.4

SHER

EKEA39

6027

.239

6036

.239

8098

.739

8180

.339

8180

.939

8190

.439

8180

.239

8192

.41

3981

93.6

539

8208

.29

3982

08.5

0539

8180

.292

3982

08.7

04

Ba

cte

ria

l W

ilt (

%)

0

20

40

60

80

100

120

Itando

Mudungu

Ivojo

On-Farm Trials in Embu District, Kenya(Linus, M., Muriithi, M. and Irungu)

� Period: 1999 – 2000

� Seed used: Certified Seed Tubers of Asante

� Surprising findings: 3.6 % (1999) and 3.2 %

(2000) of Bacterial Wilt Incidence:

“However, the farmers were advised to choose an area where

potatoes or other related crops like tomatoes had not been

planted for 3 years as precaution against possible source of

BW infection” (Linus et al., 2004)

Bacterial Wilt in Vanduzi

farm, Mozambique (2012)

Strategy 3

Appropriate Crop Rotation Systems

• Case study of Kabale (Uganda)

• Case Study of kajondi (Burundi)

Rotation Experiments in Kabale, Uganda (Lemaga, B., Kanzikwera, R., Kakuhenzire, R., Hakiza, J.J. and Maniz, G.)

� Period: 1995B – 1999A

� Site: Kachwekano (2200 masl)

� Variety: Victoria (Asante)

� Experiment 1 (one-season rotation):

maize, wheat, beans, onions, peas, cabbage,

sweetpotato, millet, carrots

� Experiment 2 (two-season rotation):

Beans – wheat/Beans – maize/Wheat –

maize/Beans – beans/Maize – maize/Wheat –

wheat

Key findings (Lemaga et al., 2001a)

�One-season Rotation:

� Maize and wheat reduced the BWI by around 18%

and significantly increased tuber yields

� Beans alone not advised as it might carry the

bacterium

� Lowest incidences with finger millet and

sweetpotato but with low yields as they are

reported to be heavy feeders (competition – need

to fertilize)

Two-season rotation:

� All rotations reduced BWI but planting 2

different crops was superior to planting the

same crop in 2 consecutive seasons

� Best rotations:

�Potatoes – beans – maize – potatoes (81 % to

21.9%)

�Potatoes – wheat – maize - potatoes

Kajondi Basic Seed Farm (Burundi)

• 300 ha arable land

• Around 25 ha of

clean basic

seed/season

• Rainfall: ca. 1400

mm/year

• Tmean: ca. 17°CSource: Google Earth

Rotation Plan in Kajondi

Hill BlockArea

(ha)98 B 99 A 99 B 00A 00B 01A 01B 02A 02B 03A 03B 04A 04B

I

1 25

2 22

3 25

III

1 20

2 26

3 20

V

1 20

2 22

Potato Maize Fallow Buckweat

WheatSource: Bizoza, 2001

Some results

Year

1993 1994 1995 1996 1997 1998 1999 2000 2001

Bacte

rial W

ilt (

%)

0.0

0.1

0.2

0.3

0.4

Pro

du

ctio

n (

x1

000

t)

150

200

250

300

350

400

Data from Bizoza, 2001

Strategy 4

Negative Selection (Rogueing)

Field detection (Rotanda, Mozambique)

Wilted

Plant

G1 Field

G2 Field

Rogueing by farmers

Example of Burundi Example of Mozambique

Strategy 5

Other Agronomic Practices

Geospatial distribution

�Toposequence of

seed plots (run-

off)

�Logical altitudinal

localization of

seed centres per

seed grade

Mugamba, Burundi

Case study: Lulimile production in Mozambique

40 kg of mini tubers1 t of G1

Tsangano,

2011

6 t of G2

Ntengo umodzi, 2012

0.6 ha of G2

Ntengo umodzi, 2012

Liming

The incidence of BW

is exacerbated

under low pH

Literature cited by Lemaga

et. al, 2001b and Linus et

al. 2004

Soil Fertilizers

Organic Manure

(Mparambo, Burundi)

Inorganic Fertilizers

(Rotanda, Mozambique)

Soil Amendments on BWI (Lemaga et al., 2001b):

� Best results when organic and inorganic fertilizers combined

� Presence of K in any combination of amendments important for both BW reduction

and yield increases

� Sesbania gave best results compared to other green manures

Key Message – Integrated Approach

1) Clean Seed

2) Pathogen Free Soil/Land

3) Appropriate Rotation Systems

4) Negative selection

5) Quality Control (Latent Infection/ELISA-Test)

6) Other Agronomic Practices (soil amendments, Volunteers, altitude of seed centers, etc…)

References• Linus, M., Muriithi, M. and Irungu, J.W. 2004. Effect of integrated use of inorganic

fertilizer and organic manures on Bacterial Wilt incidence (BWI) and tuber yield in

potato production systems on hill slopes of Central Kenya. Journal of mountain

Science, Vol. 1. (1): 81-88.

• Lemaga, B., Kanzikwera, R., Kakuhenzire, R., Hakiza, J.J. and Maniz, G. 2001a. The

effect of crop rotation on Bacterial Wilt incidence and potato yield. African Crop

Science Journal. Vol. 9 (1): 257-266.

• Lemaga, B., Sirri, D and Ebanyat, P. 2001b. Effect of soil amendments on Bacterial

Wilt incidence and yield of potatoes in Southwestern Uganda. Kinya, Z.M., Smith,

J.J., Lung’aho, C., Olanya, F. and Priou, S. 2001. On-farm successes and challenges

on producing Bacterial Wilt-free tubers in seed plots. African Crop Science Journal.

Vol. 9 (1): 279-285.

• Berrios, D. and Rubirigi, A. 1993. Integrated control of Bacterial Wilt in seed

production by the Burundi National Potato Program. ACIAR Proceedings No. 45:

284-288.

• Bizoza, F. 2001. Gestion d’un centre semencier: cas de la ferme semenciere de

Kajondi. In FAO: Techniques de Production, de Protection et de Conservation de

Semences de Pomme de terre. Proceedings of a Seed Potato Workshop held in

Bujumbura, Burundi, 2001.

Asante

Thanks

Murakoze

Ameseginalehu!

Contact: [email protected]

Photo credit: All

photos included in this

presentation, except

the Google map,

belong to the author.