Federal Department of Economic Affairs, Education and Research EAER Agroscope Genetically modified crops in Integrated Pest Management Franz Bigler, Michael Meissle and Jörg Romeis Agroscope ART Zürich, Switzerland South Asia Biosafety Conference, New Delhi, 18-20 September 2013
Why to use GM crops in the IPM context? 1. There is no single technology to solve food security problems alone in a sustainable manner. 2. The use of GM plants in the IPM context will extend lifespan of GM events and maintain high efficacy against the targets. 3. We have to learn how to make best use of GM plants in different agricultural production systems IPM sets the frame. 2
Outline What is IPM? Regionwide reduction of target pests Reduction of insecticide use Regionwide secondary pest outbreaks Effects on natural enemies and conservation biological control Insect resistance management 3
FAO definition of IPM Integrated Pest Management (IPM) means: careful consideration of all available pest control techniques integration of appropriate measures to reduce development of pest populations keep pesticides and other interventions to levels that are economically justified minimize risks to human and animal health and the environment. to grow a healthy crop with the least possible disruption to agro-ecosystems and that encourages natural pest control mechanisms. 4 Adapted from FAO Code of Conduct on Pesticide Management, 2013
The visualised IPM concept Responsive (direct) crop protection Risk assessment/ Decision making Preventive (indirect) crop protection Tolerant/ Resistant cultivars Chemical Biotechnical Physical Biological Warning/ Forecasting/ Early diagnosis systems Threshold values Resistance manag/areawide control Cultural control: Cultivation tech., Fertilizer, Irrigation, Crop rotation, Weed manag., etc. Enhancement of natural enemies Certified, healthy seeds & plants 5 Meissle et al. 2011.Pest Manag. Science,67
Resistant/tolerant plants in the IPM concept Responsive (direct) crop protection Chemical Biotechnical Risk assessment/ Decision making Preventive (indirect) crop protection Tolerant/ Resistant cultivars Physical Biological Warning/ Forecasting/ Early diagnosis systems Threshold values Resistance manag/areawide control Cultural control: Cultivation tech., Fertilizer, Irrigation, Crop rotation, Weed manag., etc. Enhancement of natural enemies Certified, healthy seeds & plants 6 Meissle et al. 2011.Pest Manag. Science,67
Effects of Bt plants in the IPM context Less insecticide use High efficacy against target pests More natural enemies in crops Lower control of non-target pests Risk of resistance build-up Region wide reduction of target pests Region wide increase of natural enemies Secundary pest outbreaks Gassmann et al. (2011) PLoS ONE 6: e22629 Tabashnik et al. (2013) Nature biotech. Less pest problems also for non- Bt growers and in other crops Wu et al. (2008) Science 321: 1676-8 Hutchison et al (2010) Science 330: 222-5 Lu et al. (2012) Nature published online Lu et al. (2010) Science 328: 1151-4 7
Outline What is IPM? Regionwide reduction of target pests Reduction of insecticide use Regionwide secondary pest outbreaks Effects on natural enemies and conservation biological control Insect resistance management 8
Targets of commercial Bt crops Cotton Maize Bollworms: Heliothis virescens Helicoverpa zea/armigera Erias spp. Pink Bollworm: Pectinophora gossypiella 17+ other lepidopteran pests 8+ other lepidopteran pests Caterpillars: Ostrinia nubilalis/furnacalis Sesamia nonagrioides Diatraea spp. Helicoverpa zea/armigera Spodoptera frugiperda Rootworms: Diabrotica spp.
Areawide suppression of Ostrinia nubilalis with Bt maize in 5 US states Bt maize as a trap crop of the key pest Mean number of larvae/100 plants 10 Hutchison et al. 2010, Science
Cumulative benefits ($ Billions) of Bt maize in 5 US states States: MN, WI, IL States: IA, NE Hutchison et al. 2010, Science 11
Bt cotton as trap crop to reduce Helicoverpa armigera in non-bt cotton in northern China (average of 38 locations) Non-Bt cotton Bt cotton Non-Bt cotton Bt cotton 12 Wu et al. 2008, Sience Planting year of Bt cotton
Outline What is IPM? Regionwide reduction of target pests Reduction of insecticide use Regionwide secondary pest outbreaks Effects on natural enemies and conservation biological control Insect resistance management 13
Bt crops reduce insecticide use and increase yield Country Insecticide Yield Argentina - 47 % + 33 % Australia - 48 % 0 China - 65 % + 24 % India - 41 % + 37 % Mexico - 77 % + 9 % South Africa - 33 % + 22 % USA - 36 % + 10 % Country Insecticide Yield Argentina 0 + 9 % Philippines - 5 % + 34 % South Africa - 10 % + 11 % Spain - 63 % + 6 % USA - 8 % + 5 % Qaim (2009) Annu Rev Resour Econ 1: 665-93 Gómez-Barbero et al. (2008) Nat Biotechnol 26: 384-6 14
Yield increase, pesticide reduction and financial gain on resource-poor cotton farms in India and China Mannion & Morse 2012, Prog. Phys. Geogr. 15
Insecticide use patterns in the USA cotton 1986-2009 Texas A&M Univ. Bt cotton introduced 50% red. 70% red. 16 (Naranjo, 2011)
Outline What is IPM? Regionwide reduction of target pests Reduction of insecticide use Regionwide secondary pest outbreaks Effects on natural enemies and conservation biological control Insect resistance management 17
Mirid bug outbreaks as a function of Bt cotton planting proportion 1997-2008 Bt cotton planting proportion in northern China and Mirid bug populations (38 locations) 0.2 0.4 0.6 0.8 1 Mirid bug insecticide treatments in cotton in 38 locations 1997 2008 Lu et al. 2010, Science 18
Mirid bug outbreak in other crops after widespread use of BT cotton in northern China Bt cotton planting proportion in northern China and Mirid bug populations (38 locations) 0.2 0.4 0.6 0.8 1 Mirid bugs Infestation level Cotton Apple Grape Peach Pear Chin. date Bt cotton planting proportion 19 Lu et al. 2010, Science
Outline What is IPM? Regionwide reduction of target pests Reduction of insecticide use Regionwide secondary pest outbreaks Effects on natural enemies and conservation biological control Insect resistance management 20
Reduction of pesticide use in cotton preserves general predators Insecticide treatments/year Bt Cotton at 36 localities in northern China Treatments H. armigera Lu et al. 2012, Science All treatments Arthropod pred /100 cotton plants Aphids/100 cotton plants 21
Arthopod predator density on cotton and in three other crops in northern China Soybean Predators /100 cotton plants Arthropod predators /100 cotton plants Predators /100 plants in peanut, maize and soybean Maize Peanut 22 Lu et al. 2012, Science Predators /100 cotton plants
Outline What is IPM? Regionwide reduction of target pests Reduction of insecticide use Regionwide secondary pest outbreaks Effects on natural enemies and conservation biological control Insect resistance management 23
Insect Resistance Management What is insecticide resistance? Resistance (is) a genetic change in response to selection by toxicants that may impair control in the field (Sawicki, 1987) Development of strains capable of surviving a dose lethal to a majority of individuals in a normal population (Constant and Roush, 1990) Resistance is a heritable change in the sensitivity of a pest population that is reflected in the repeated failure of a product to achieve the expected level of control (IRAC cited in Tabashnik et al, 2013) 24
Present status of resistance to Bt plants Five confirmed cases of field resistance (Tabashnik et al. 2013) Helicoverpa zea; USA, against Cry1Ac cotton in 2002 after its indtroduction in 1996 (6 years) Spodoptera frugiperda; Puerto Rico, against Cry1F maize in 2007 after its introduction in 2003 (4 years) Busseola fusca; South Africa, against Cry1Ab maize in 2004 after its introduction in 1998 (6 years) Pectinophora gossypiella; India, against Cry1Ac cotton in 2009 after its introduction in 2002 (7 years) Dibarotica virgifera virgifera; USA, against Cry3Bb1 in 2010 25
High dose/refuge strategy High dose: to kill 99.9 of susceptible individuals of a population RS SR Refuge: to reduce chances that resistant insects (RR) mate with each other by providing large numbers of susceptible insects (SS) from the refuge (non-bt crop or other crops) Bt RR RR non Bt SS 26
Factors affecting the efficacy of insect resistance management strategies Inheritance of resistance (initial resistance frequency, recessive/dominant) Toxin dose (level over growing season) Refuge Size and placement Farmer compliance Expression of multiple toxins (pyramids) Fitness costs of resistance Impact of natural enemies 27
Conclusions Current Bt crops play a major role in IPM systems of cotton and maize with benefits to farmers and the environment High efficacy of Bt crops against target insect pests reduce pest populations regionwide Bt crops reduce insecticide use and thus enhance natural enemies in the target crop itself and in other crops regionwide Biological control organisms are not negatively affected by Bt crops which are more IPM compatible than most insecticides Intelligent resistance management will be a key for sustainable use of Bt crops IPM is a continuous learning process on how to optimize methods and technologies including GM crops 28
Thank you for your attention 29
Supplement to the FAO IPM concept Important additional points are listed in the Directive on Sustainable Use of Pesticides of the European Union: Preventive (indirect) control measures are the 1st choice Non-chemical methods (biological, biotechnical, physical) are the preferred direct control measures Pesticides are the last option of direct measures EU Directive 2009/128/EC, Chapter 1, Art. 3 30
Bt cotton as areawide trap crop for Helicoverpa armigera in other crops H. armigera 2nd gen. in cotton H. armigera 2nd gen. in maize, peanuts, soybean, vegetables H. armigera 3rd gen. in cotton H. armigera 3rd gen. in maize, peanuts, soybean, vegetables Planting year of Bt cotton Wu et al. 2008, Science Planting year of Bt cotton 31
Bt plants preserve natural enemies Effects of Bt plants on natural enemies compared to: Conventionel no insecticides Conventionel with insecticides Negativ Positiv Naranjo 2009, CAB Rev. 32
Effects of Bt crops on abundance of biological control insects compared to unsprayed non-bt crops Effect size 0.6 0.4 0.2 0.0-0.2-0.4 18 Explanation: Geocoris 93 39-0.6 Marocentrus grandii, a specialist parasitoid of -0.8 the European corn borer is absent in Cry1Abexpressing Bt maize. -1.0-1.2 Non-Bt maize refuges preserve M. grandii. Wolfenbarger et al. 2008, PLoS One 37 93 Orius Chrysoperla Coleomagilla Macrocentrus 33