Biological Control of Aflatoxin: Experience and lessons learnt from Senegal and the Gambia

Dr. Amadou Lamine SENGHOR

REPUBLIQUE DU SENEGAL, MINISTERE DE L’AGRICULTURE ET DE L’EQUIPEMENT RURAL

DIRECTION DE LA PROTECTION DES VEGETAUX

For years after independence 1960, the dominant crop in

Senegal was peanut.

It represented over 80 % of the country’s exports, covered half

the cultivated area, and employed 87 percent of the active

population (Caswell, 1985).

0

200,000

400,000

600,000

800,000

1,000,000

1,200,000

1,400,000

1,600,000

QU

AN

TIT

Y G

RO

UN

DN

UTS (

MT)

Year

Quantity of output (Mt)

Quantity 0f export (Mt)

(Yiadom, 2003)

Aflatoxin in Peanut oil from Diourbel and Kaolack Regions

(Bathily, 1998):

Aflatoxin

Oil samples from Diourbel

Oil samples from Kaolack

B1 24 ± 14 42 ± 32

B2 13 ± 10

G1 23 ± 20 7 ± 4

G2 6 ± 2

TOTAL (B1, B2, G1, G2)

40 ± 27

59 ± 34

(Bathily, 1998): 85% of aflatoxin remains in the cake after extraction (Basappa and Sreenivasa, 1974)

Aflatoxin in Peanuts’ Cake from Diourbel and kaolack Regions

Aflatoxin

Cake samples from Diourbel

Cake samples from Kaolack

B1 91 ± 64 134 ± 52

B2 79 ± 58 68 ± 26

G1 76 ± 17 16 ± 14

G2 45 ± 22 16 ± 14

TOTAL (B1,

B2, G1, G2)

199 ± 94

220 ± 105

Aflatoxin in groundnut Samples from Seven Regions of

Senegal

Level of aflatoxin (ng/g)

Districts B1 B2 G1 G2

Means Means Means Means

Diourbel 96 30 35 27

Kaolack 73 30 44 20

Kafrine 38 4 12 2

Kolda 25 8 11 3

Fatick 16 14 21 12

Tamba 5 2 0.38 3

Ziguinchor 2 6 4 3

LSDa 80 15 19 11 aLess significant difference test (P=0.05) to compare means of grain samples from 8 regions in Senegal(Senghor et al., 2012)

Aflasafe: Transferring Aflasafe SN01 to the field

In 2007, a survey was made for soil, maize and sesame

sampling to isolate atoxigenic A. flavus for biocontrol use.

Collaboration between IITA and the University of Thiès.

Fields inoculation in Nioro and Diourbel

Teams recruited for area treatment of fields in 6 village at the peanut basin Senegal in 2012

Soil sampling before inoculation

Treatment with Aflasafe

Threshing at harvest Packaging sample in two sets

Sample collection

Extraction and toxin analysis of samples

Table 5. Aflatoxin concentration at harvest in Groundnut samples from fields treated with Aflasafe SN01 and their controls in 2010, 2011 and 2012.

Aflatoxin concentration (ng/g)2

2010

2011

2012 Area Treatment Mea

n3

Reduction

(%)4

Mean3 Reduction

(%)4

Mean3 Reduction

(%)4

aflasafe

SN01 1.9 b 93.4

6.6 b 86.9

3.7 b

81.8

Diour-

bel

Control 29.7a

50.1 a

20.3 a

Nioro

aflasafe

SN01 4.4 b 75.3

5.6 b 75.8

5.4 b

90.4

Control 17.6a

23.1 a

55.7 a

1. In 2010 and 2011 there were 20 farmers’ fields in Diourbel and 20 farmers’ fields in Nioro

regions each for both control and aflasafe SN01 treatments. In 2012, there were 17 farmers’ fields

in Diourbel and 71 farmers’ fields in Nioro each for control and Aflasafe SN01 treatments. Samples

for aflatoxin analysis were processed immediately after harvest.

2. Aflatoxin B was the sum of aflatoxin B1 and B2.

3. Means within each column, for each year with different letters are significantly different

according to the t-test at 5% level of probability.

4. Reduction (%) = ([mean of control - mean of aflasafe SN01 treated]/mean of control) × 100.

Table 6. Aflatoxin concentration at harvest in Groundnut samples from fields treated with Aflasafe SN01 and their controls after four month of storage at farmers conditions in 2010, 2011 and 2012.

Aflatoxin concentration (ng/g)2

2010

2011

2012

Area Treatment Mean3

Reduction

(%)4

Mean3 Reduction (%)

4 Mean

3 Reduction (%)

4

aflasafe

SN01 4.4 b 85.8

2.1 b 90.7

6.9 b

80.7

Diour-

bel

Control 31.3 a

22.1 a

35.5 a

Nioro

aflasafe

SN01 3.5 b 95.2

2.8 b 94.1

11.5 b

84.2

Control 52.1 a

46.7 a

72.5 a

1. In 2010 and 2011 there were 20 farmers’ fields in Diourbel and 20 farmers’ fields in Nioro regions

each for both control and aflasafe SN01 treatments. In 2012, there were 17 farmers’ fields in

Diourbel and 71 farmers’ fields in Nioro each for control and aflasafeTM SN01 treatments. Samples

for aflatoxin analysis were processed three months after storage in farmers’ storage conditions.

2. Aflatoxin B was the sum of aflatoxin B1 and B2.

3. Means within each column, for each year with different letters are significantly different according

to the t-test at 5% level of probability.

4. Reduction (%) = ([mean of control - mean of aflasafe SN01 treated]/mean of control) × 100.

Fig. 1. Gambia road map with the 7 ground nuts major producing regions

Tester Pairs Positive

Isolates

Locations/

Regions

A E Z

M2-7 GMG 72-8 URR South SG

GMG 72-9 U R R South SG

GMG 20-10 W C R Gambia SG

GMG 87-9 URR North SS

GMG 105-14 C RR North SS

MS14-19 GMG 35-7 L R R Gambia SG

GMG 107 - 1 C RR North SS

M21-11 GMG 72-12 UR R South SG

SS19-14 GMG 72-3 U RR South SG

GMG72-4 U RR South SG

GMG72-6 U R R South SG

GMG 72 - 7 U R R South SG

2014 Growing Season

Make use of Aflasafe by all Groundnut and Maize producers by including Aflasafe in NAIP Senegal: Already proposed and accepted

Training of farmers on the use and adoption of Aflasafe by ANCAR

Creating a market for Groundnut treated with Aflasafe (SODEFITEX)

Production and marketing of Aflasafe SN01

Continue sensitization by the media (TV and Radio broadcasting programs)

African Agricultural Technology Foundation (AATF)

USDA-ARS, IITA

ACKNOWLEDGEMENTS