can genetically modified plants play a role in sustainable ... · can genetically modified plants...

Can genetically modified plants play a

role in sustainable crop protection?

Franz Bigler, Olivier Sanvido and Jörg Romeis

Agroscope Research Station ART

Zürich, Switzerland

Crop losses in major crops and the role

of crop protection

Oerke and Dehne (2004) Crop Protection 23:275-285

83

82

80

71

66

60

50

48

27

30

42

39

33

28

29

27

0 20 40 60 80 100

Sugar beet

Cotton

Rice

Potatoes

Maize

Soybean

Wheat

Barley

Crop loss rate (in % of attainable yield)

Actual loss (despite crop protection)

Potential loss (without crop protection)

Global adoption rates of GM crops 2008

Maize

30%

Cotton

12%

Oilseed rape

5%

Soybean

53%

by crop by trait

James 2008 ISAAA brief no. 39

Insect

resistance

(IR); 15% Herbicide

tolerance

(HT); 63%

stacked; 22%

Integrated Pest Management – a

sustainable way of crop protection

Integrated Pest Management (IPM) is a

crop protection strategy utilising all

suitable methods and techniques which

are compatible with economic, ecological

and social requirements to keep damaging

organisms below economic injury levels

(FAO 1965 & 1980)

Integrated Pest Management – a

sustainable way of crop protection

Integrated Pest Management (IPM) is a

crop protection strategy utilising all

suitable methods and techniques which

are compatible with economic, ecological

and social requirements to keep damaging

organisms below economic injury levels

(FAO 1965 & 1980)

New EU directive requesting IPM of all EU

farmers by 2014

Pest Biology& Ecology

Culturalcontrol

Quarantine,Eradication

Sampling,Monitoring & Forecasting

Economic thresholds

Pesticides etc.

Resistance Manag.

Avoidance,Prevention

Pesticides & other direct methods

Integrated PestManagement

Sampling,Thresholds

(Courtesy of Steven Naranjo, adapted)

Biological control

Host plantresistance

The ideal pest resistant plant from an IPM

perspective?

1. Control of key pests with high efficacy (below economic injury level)

2. No/less direct control measures needed (e.g. insecticides)

3. No resurgence of target pests

4. Non-target pests have same or lower pest status (no secondary pest outbreaks)

5. No adverse effects on natural enemies (biological control)

6. Preservation of other ecosystem services (e.g. pollination, decomposition)

7. Low risk of pest resistance

8. No negative landscape effects (e.g. ecological functions preserved)

9. Economic benefits (e.g. high yield and quality)

10. Social benefits (e.g. low toxicological risks)

Control of key arthropod pests by

commercialized Bt crops

Bt cotton (Naranjo et al. 2008)

28 lepidopteran pest species listed:

9 excellent control, 13 good control, 5 some control, 1 no control

No control of Hemiptera, Coleoptera, Thysanoptera, Acari

Bt maize (Hellmich et al. 2008)

15 lepidopteran pest species listed:

7 stemborers (5 excellent control, 2 good control)

8 other Lepidoptera (3 good control, 4 some control, 1 no control)

1 coleopteran pest with good control

No control of Hemiptera, other Coleoptera, Diptera, Thysanoptera,

Acari

Country Number of

sprays

% change

Pesticide

(Kg/ha)

% change

Yield

% change

Refs

Argentina -52 -55 +32 Qaim et al., 2003

USA -35 +3 Williams, 2003;

Cattaneo et al., 2006

Australia -80 -85 +0.5 Fitt 2003, 2005;

Pyke 2004, 2007

India -42 -65 +75 to + 230 Qaim 2003;

Qaim & Zilberman 2003;

Bamberwale et al., 2004

China -60 -70 + 3 to +19 Pray et al., 2002;

Huang et al., 2003;

Lu et al., 2002

Sth Africa (small

farms)

-56 -24 +34 to +80 Yousef et al., 2001;

Ismael et al., 2002;

Kirsten et al., 2002;

Bennett et al., 2003;

Hofs et al., 2006

Sth Africa (large

farms)

-56 +20 Kirsten et al., 2002;

Gouse et al., 2003

Mexico -54 +11 Traxler et al., 2001

Bt cotton - impact on insecticide use and yield(Fitt, 2008)

Effects of Bt crops on abundance of biological control insects

compared to unsprayed non-Btcrops

GeocorisOriu

s

Chrysoperla

Coleomagilla

Macrocentrus

Eff

ec

t s

ize

-1.2

-1.0

-0.8

-0.6

-0.4

-0.2

0.0

0.2

0.4

0.618

93 3993

37

Wolfenbarger et al. 2008, PLoS OneCourtesy of S. Naranjo

Effects of Bt crops on abundance of biological control insects

compared to unsprayed non-Btcrops

GeocorisOriu

s

Chrysoperla

Coleomagilla

Macrocentrus

Eff

ec

t s

ize

-1.2

-1.0

-0.8

-0.6

-0.4

-0.2

0.0

0.2

0.4

0.618

93 3993

37

Wolfenbarger et al. 2008, PLoS One

Explanation:

Marocentrus grandii, a specialist parasitoid of

the European corn borer, is absent in Bt maize

because of absence of its target host.

Effects of Bt plants on

conservation biological

control

Natural enemy abundance and biological control are

significantly enhanced in Bt crops when compared

to insecticide-treated conventional fields

Romeis et al. (2006) Nature Biotechnology 24: 63-71

Marvier et al. (2007) Science 316: 1475-1477

Wolfenbarger et al. (2008) PLoS ONE 3(5): e2118

Meadows

Orchards

Hedges

Fallows

WheatMaize

Potential landscape

effects of GM crops

Potential landscape effects of GM crops

4 scenarios under GM crops adoption and IPM implications:

• Stable crop area reduced pesticide use with positive

effects on biodiversity and ecosystem services (e.g.

biocontrol, pollination)

• Increased crop area (additional incentives): less diverse crops

and non-crop areas may reduce ecosystem services

(e.g. biofuel production, see Landis et al. 2008)

• Areawide reduction of target pest(s) less pesticide use

(e.g. pink bollworm USA) positive effects on landscape level

• Areawide increase of non-target pests (secondary pest

outbreaks) negative landscape level effects (depending

e.g. on additional pesticide use)

Country N Sprays

% change

Pesticide

(Kg/ha)

% change

Yield

% change

Refs

Argentina -52 -55 +32 Qaim et al., 2003

USA -35 +3 Williams, 2003;

Cattaneo et al., 2006

Australia -80 -85 +0.5 Fitt 2003, 2005;

Pyke 2004, 2007

India -42 -65 +75 to + 230 Qaim 2003;

Qaim & Zilberman 2003;

Bamberwale et al., 2004

China -60 -70 + 3 to +19 Pray et al., 2002;

Huang et al., 2003;

Lu et al., 2002

Sth Africa (small

farms)

-56 -24 +34 to +80 Yousef et al., 2001;

Ismael et al., 2002;

Kirsten et al., 2002;

Bennett et al., 2003;

Hofs et al., 2006

Sth Africa (large

farms)

-56 +20 Kirsten et al., 2002;

Gouse et al., 2003

Mexico -54 +11 Traxler et al., 2001

Bt cotton - impact on insecticide use and

yield (Fitt, 2008)

Conclusions

• Current GM crops play a major role in some

IPM systems with benefits for farmers and the

environment

• GM crops have broadened opportunities for

other IPM tactics such as biological control

• Intelligent resistance management will be a

key for sustainable use of GM crops in IPM

• Pest resistant GM plants must be seen as an

IPM component that can be optimized

Biological

control

Pest Biology

& Ecology

Cultural

control

Cross-

Commodity

AreawideHost plant

resistance

Detection

Sampling & Monitoring

Thresholds

Insecticides

Resistance Manage.

Challenges for research

• How to reduce crop losses (mainly in the developing

world) and what can GM plants contribute to food

security?

• How to integrate GM plants in sustainable

agricultural systems incl. organic agriculture?

• How can new technologies in agriculture get trust by

the public (not only GM plants)?

• Social sciences have to play a stronger role

Thank you for your attention

Outline

• Crop loss and crop protection

• Integrated Pest Management (IPM) - a

sustainable crop protection strategy

• The ideal pest resistant GM plant?

• GM crops, IPM and the landscape

• Resistance management of IR GM crops

• Economics and social aspects

Impact on non-target pests – a meta-

analysisE

ffe

ct

siz

e

-1.6

-1.2

-0.8

-0.4

0.0

0.4

0.8

1.2

140

95

19

7

8

31

Cotton Maize Plant

bugs

Stink

bugs

Aphids Whiteflies

Courtesy of S. Naranjo 2009 Wolfenbarger et al. 2008

IPM and the concern of pest resistance

• Resistance of pests is a general concern in crop protection (>

550 arthropod pests have developed resistance to pesticides)

• Prevention measures are:

a) use of avoidance strategies (e.g. crop rotation,

resistant plants),

b) combining technologies (e.g. resistant plants,

biological control, field sanitation),

c) use of alternating chemical compounds.

Resistance management of Bt crops includes: high

dose/refuge strategy and stacked Bt genes expressing

several Cry types.

ongoing debate of evolved field resistance of Helicoverpa zea

in Bt Cry1Ac cotton (Tabashnik at al. 2008, Moar et al. 2008)

Increasing number of HT crops (with same a.i.) increases risk

of resistant weeds

Biological

control

Pest Biology

& Ecology

Cultural

control

Cross-

Commodity

AreawideHost plant

resistance

Detection

Sampling & Monitoring

Thresholds

Insecticides

Resistance Manage.

Survey of health impact of Bt cotton on

farmers in China

Number of

farmers in

survey

Pesticide

quantity

(kg/ha)

% farmers

reporting

poisoning

Bt cotton only 316 18 9

Bt and non-Bt 61 29 26

Non-Bt cotton

only

30 46 33

Hossein et al. 2004

Global biotech area 2008

by country

USA

50%

Argentina

17%

Brazil

13%

Canada

6%

India

6%

China

3%

South Africa

1%various

2%Paraguay

2%

Clive James, 2008