Effective aflatoxin management in farmers' fields in West and East Africa

www.iita.org A member of CGIAR consortium

Effective Aflatoxin Management in

Farmers' Fields in West and East

Africa

IITA: Bandyopadhyay, Atehnkeng, Mutegi

USDA-ARS / Univ of Arizona: Cotty,

Jaime-Garcia, Callicot, Probst

Senegal: Senghor; Burkina: Bonkoungou

Annual Meeting of the American Phytopathological Society

Minneapolis, 9-13 August, 2014

• Highly toxic metabolite produced by the ubiquitous Aspergillus flavus fungus

• The fungus resides in soil and crop debris, infects crops and produces the toxin in the field and in stores

• Death, liver cancer, immune-suppression, stunted growth

• Impacts animal productivity

• Negatively impacts trade

• Fungus carried from field to store

• Contamination possible without visible signs of the fungus

Aflatoxin Facts


Pre-Harvest Problem

Aflatoxin (ppb)ppb)

Peanut (n = 188) Maize (n = 241)

Distribution (% samples)

> 4 54 70

> 10 41 52

> 20 29 24

Descriptive statistics (ppb)

Minimum < LOD < LOD

Maximum 3487 838

Mean 111 33

LOD = Limit of Detection; 1 ppb

Aflatoxin in Groundnut and Maize at Harvest

Increases in store


EPA approved 2 products

AF36

Afla-guard

Hundreds of

Thhosands of acres treated

annually in the US!

Production Room

Atoxigenic Strain Manufacturing Facility

Arizona Cotton Research & Protection Council

(Funded and Governed by the Farmers of Arizona),

Phoenix, Arizona

It Works in Africa Too

Biocontrol Works!

www.iita.org

• IITA

• USDA

• AATF

• BMGF/USAID

• Doreo Partners

• National institutions

Strong Partnership



Biocontrol Principles

In nature, some strains produce a lot

(toxigenic), and others no aflatoxin

(atoxigenic) (Donner, Soil Biol Biochem

2009)

Atoxigenic strains are already present on

the crop (Atehnkeng et al., IJFM, 2008)

Increase the frequency of atoxigenic

strains to competitively displace

toxigenic strains (Cotty & Bayman,

Phytopath 1993) to reduce aflatoxin

contamination .

Atoxigenic strains can be applied without

increasing infection and without

increasing the overall quantity of A. flavus

on the crop or in the environment (Cotty,

Phytopath 1994; Atehnkeng et al., Biological

Control 2014)

0

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4

5

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8

9

0 20 40 60 80 100Afl

ato

xin

B1 (

ng

/g X

10,0

00)

Isolates (%) in Applied Atoxigenic Strain

Strains move from

field to stores

Multiple year & crop

carry-over effect

(Jaime & Cotty,

Phytopath 2006) We use only native

strains


Strain Selection Criteria

In the laboratory (~5,000 strains):

• Does not produce aflatoxin

• VCG/SSR group with

Wide geographic distribution

No toxigenic member

• Defective in >2 aflatoxin & CPA

genes

• Outcompetes toxigenic strains

After field application:

• Superior capacity to colonize,

multiply and survive in soil

• Superior frequency of isolation

from grains

• Superior capacity to reduce

aflatoxin 8-12 native strains

selected for field tests

4 native strains

formulated into

the final

product

Broadcast @ 10 kg/ha 2-3 weeks before flowering

Sporulation on moist soil

Spores

Insects

Aflasafe in 5 kg boxes

3-20 days

Wind

Soil colonization

30-33 grains m-2

Fungal network in killed grain

How Does aflasafe Work?


Efficacy Trials: Data Collection

• All trials conducted in farmers’ fields on crops grown by farmers

• Aflasafe applied by farmers

• Soil sampled before treatment and grains at harvest:

– Aspergillus population density

– Aspergillus strain profile

– Incidence of aflasafe strains

• Aflatoxin concentration in grains at harvest and after poor storage


Design & Analysis of Trials

• Field trial size: 0.25 to 15 ha

• Number of fields: 14 to 200 per year

• Paired plot: Each treated field with its own companion control field in close vicinity

• Each farmers’ field considered as a replicate

• Student’s t-test to compare treatment effects


Nigeria: Efficacy on Maize

372

0

20

40

60

80

100

120

2009 2010 2011 2012

Aflasafe™ Control

0

100

200

300

400

500

600

2009 2010 2011 2012

82 94 83 86 82 93 89 90

51 14 199 38 51 14 166 38 Fields (#)

Less (%)

At Harvest After Storage

*All means of aflasafe and control pairs significantly different; Student’s t-test (P<0.05)

*

Aflato

xin

(ppb)


Crop Sample Treatment Fields AF

mean (ppb)*

Red uction

(%)

Groundnut

Harvest Treated 51 3.7

92 Control 51 44.0

Storage Treated 49 15.0

86 Control 49 101.0

Maize

Harvest Treated 17 1.7

82 Control 17 9.1

Storage Treated 17 50.3

84 Control 17 319.0

*All means of aflasafe treated and control pairs

significantly different; Student’s t-test (P<0.05)

Efficacy trial sites

Crop sampling sites

Burkina: Efficacy of aflasafe BF01 2012

https://www.google.co.uk/imgres?imgurl&imgrefurl=http://www.21food.com/products/maize,-soya-been-seeds,-yellow-millet,-rice,-sesame-seeds,-peanuts,-mustard-seeds,-safflower-seeds,-703431.html&h=0&w=0&sz=1&tbnid=tdT0FRuWx4Sc0M&tbnh=259&tbnw=194&zoom=1&docid=91ikF3dq8zDWFM&ei=aGiOUpCNAc-T0AW5w4H4CQ&ved=0CAIQsCU


Area Sample Treatment Mean

Aflatox (ppb)

Reduct. (%)

Mean Aflatox (ppb)

Reduct. (%)

Mean Aflatox (ppb)

Reduct. (%)

Diourbel

Harvest Treated 1.9

93 6.6

87 3.7

82 Control 29.7 50.1 20.3

Storage Treated 4.4

86 2.1

91 6.9

81 Control 31.3 22.1 35.5

Nioro

Harvest Treated 4.4

75 5.6

76 5.4

90 Control 17.6 23.1 55.7

Storage Treated 3.5

95 2.8

94 11.5

84 Control 52.1 46.7 72.5

*All means of aflasafe treated and control pairs significantly different; Student’s t-test (P<0.05)

Senegal: Efficacy of aflasafe SN01

2010 (n=40) 2011 (n=34) 2012 (n=71)


Basis of efficacy: species shift

Treatment (n = 14)

Aspergillus species/strain distribution (%) – MAIZE/NIGERIA

Soil before inoculation Grain at harvest L SBG parasiticus L SBG parasiticus

Aflasafe™ 90 aB 7 aA 3 aA 100 aB 0 bA 0 aA

Control 78 aB 15 aA 7 aA 83 bB 16 aA 0.3 aA

Means within the column with different lowercase letters are significantly different according to the t-

test at 5% level of probability. Means within the row with different uppercase letters are significantly

different according to the Fisher’s LSD test at 5% level of probability

Region

Treatment

Aspergillus Colony Forming Units/g – G-nut/Senegal 2010 (n = 20) 2011 (n = 17)

Soil Kernel Soil Kernel

Diourbel Control 2311 a 2912 a 474 a 3257 a

Aflasafe SN01 1793 a 3598 a 795 a 3965 a

Nioro Control 228 a 3367 a 369 a 3572 a

Aflasafe SN01 120 a 3189 a 470 a 4275 a

*All means of aflasafe and control pairs significantly different; Student’s t-test (P<0.05)

Aspergillus population does not increase due to aflasafe application

No change in Aspergillus Pop.


Bars with same letter within the same

crop/year not significantly different (P<0.05)

Basis of Efficacy: Strain Shift

0

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60

70

80

90

Soil Grain Soil Grain

2009 (n = 49) 2010 (n = 14)

Control Treated

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90

Soil Grain Soil Grain

2009 (n = 2) 2010 (n = 16)

Proportion of 4 aflasafe™ strains in soil before treatment

and grains after harvest in control and treated fields

Afl

asafe

str

ain

s (

%)

a a a a a a a a a a a a

b b b

b

Carry-over of inoculum: 71, 52

and 28% after 1, 2, and 3 years

http://www.google.co.uk/url?sa=i&rct=j&q=&esrc=s&frm=1&source=images&cd=&cad=rja&docid=lKk0dkUswMQkNM&tbnid=iNOHk0UxXmQVFM:&ved=0CAUQjRw&url=http://naijaintellect.wordpress.com/2012/07/26/nigerian-govt-releases-two-new-hybrid-maize-varieties/&ei=2BeSUsG8EKeH0AXah4DICw&bvm=bv.56988011,d.ZG4&psig=AFQjCNEwOZ2zmi8Rt6wdDo6BOODAz2xl1g&ust=1385392435580697


Kenya: Efficacy of aflasafe KE01™

Area (fields) Control Treated Reduction

(%)

Hola (n = 20) 885 20 98

Bura (n = 16) 105 7 93

Makueni (n = 15) 85 1 99

Aflatoxin (ppb)

*All means of aflasafe treated and control pairs significantly different; Student’s t-test (P<0.05)

38

20

0

88

60

33

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40

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60

70

80

90

100Treated

Control

Fields (%) above 10 ppb in 3 areas

Fie

lds (

%)

Deadly (3,700 ppb & 2,270 ppb)

533 ppb

Hola

74 ppb - Treated

1,133 ppb - Control

93.5% Reduction

Mutomo, Kitui County, Kenya: 2012 Tests

Short Rain Season Farmer Field Trials

Deadly

Average 2,750 ppb!

Range 1,790 ppb to 3,710 ppb.

Safe Food

510 ppb

Percent of Fields

Tota

l Aflato

xin

s (

ppb)


Product Development in Africa

Products ready for registration

Products under testing

Strain development in progress

Senegal Mali

Burkina

Ghana

Nigeria

Kenya

Tanzania

Mozambique

Zambia

Rwanda

Burundi

Uganda

2015

onwards

Benin Togo Ivory Coast Ethiopia South Sudan Malawi Sierra Leone …………

The Gambia


Groundnut sampling in The Gambia (2013)

• Number of samples/region = 20 (4 villages per region; 5 samples per village) = 140

• Aflatoxin analyzed in all 140 samples

• Samples plated on semi-selective medium; 12 Aspergillus isolates / sample (except 6)

• Isolates characterized into species and strains; 72% L; 27% SBG and 1% parasiticus

• All L-strain isolates interrogated for presence of the four aflasafe SN01 VCGs


Aflatoxin in Groundnut in The Gambia

Regions*

Total Aflatoxins (ppb)

Mean Median Minimum Maximum

West Coast 268 19 ND 1,845

Lower River 3 ND ND 21

Upper River South 17 1 ND 208

Upper River North 5 1 ND 44 Central River South 39 7 ND 253 Central River North 102 13 ND 1,157

North Bank 102 23 ND 526

*Number of samples/region = 20 (4 villages per region; 5 samples per village)

Incidence


Aflatoxin in Groundnut in The Gambia

Regions*

Samples (%) with Total Aflatoxins (ppb)

ND → 4 >4 → 20 >20 → 100 >100

West Coast 40 10 10 40

Lower River 85 10 5 0

Upper River South 60 25 10 5

Upper River North 85 5 10 0 Central River South 45 30 10 15 Central River North 35 25 20 20

North Bank 40 10 20 30

*Number of samples/region = 20 (4 villages per region; 5 samples per village)

Severity


Aflasafe SN01 VCG is Native in The Gambia

Aflasafe SN01 VCG

Gambian members of VCG

Present in Locations/Region

s Number Name

M2-7 5

GMG 72-8 Upper River South GMG 72-9 Upper River South GMG 20-10 West Coast GMG 87-9 Upper River North GMG 105-14 Central River North

MS14-19 2 GMG 35-7 Lower River GMG 107-1 Central River North

M21-11 1 GMG 72-12 Upper River South

SS19-14 4

GMG 72-3 Upper River South GMG 72-4 Upper River South GMG 72-6 Upper River South GMG 72 - 7 Upper River South

www.iita.org www.iita.org A member of CGIAR consortium R4D week, 25 – 30 Nov.

2013

Integrated approach to manage aflatoxins in crops

AgResults Aflasafe Pilot -- 2013


Some key statistics

• Number of implementers: 4

• Number of farmers: 1,015

• Treated area: 1,457 ha

• Average productivity: 4.3 tons/ha

• Maize aggregated for sale: 2,031 tons

• Samples with <4 ppb AF (n = 660): 99%

• Samples with >70% aflasafe strains

(n = 88): 65% to 100%

• Return on investment: Up to 510%

• Aflasafe maize kept for family (n = 60): 46%


Aflasafe Return on Investment

Quantity sold

(tons) Premium

(%) Premium

(USD)

Aflasafe cost

(USD)

Finance cost

(USD)

Net profit (USD)

Seasonal RoI

AgResults Premium

(USD)

Total Profit (USD)

Total RoI

120.0 7.5% 3,000 836 146 2,017 241% 1,800 3,817 456%

150.0 7.5% 3,750 1,046 183 2,521 241% 2,250 4,771 456%

96.0 3.6% 1,200 669 117 414 62% 1,440 1,854 277%

128.0 13.2% 5,600 892 156 4,552 510% 1,920 6,472 725%

32.0 7.5% 800 223 39 538 241% 480 1,018 456%

30.1 1.8% 188 210 37 -58 -28% 452 393 187%


Scaling-Out

• Nigeria: AgResults (260,000 t) • Senegal: Area-wide treatment in

2013; about 8 tons used • Kenya: Government buy-in;

excellent support • Zambia: Large-scale efficacy tests

and demonstration of product value with private sector (12 t)

• Need for business plan, manufacturing capacity, marketing and distribution strategies

• Critical role of PACA and RECs


Aflasafe Manufacturing Facility

Large-scale: capacity 5 tons/hour

• Aflatoxins in food and feed pervasive in Africa

• Biological control, as the foundation, with other practices can dramatically reduce aflatoxin contamination and improve food safety and security

• Efforts underway to pilot commercialization of aflatoxin biocontrol and develop regional strains

• The pilots need to be up-scaled and efforts to improve efficacy needs a fillip for wide-spread impact on health and trade in Africa

Summary

IITA

Tucson

USDA/ARS IITA, USDA, & Doreo have Teamed up to Bring

Aflatoxin Prevention to Africa

Made Possible by Many National Partners in Ministries, Industry, and on the Farm

Nigeria

For more information about aflatoxin biocontrol for Africa, check out: www.aflasafe.com

http://www.entwicklung.at/en/

Science

Effective aflatoxin management in farmers' fields in West and East Africa