From entomology in Bologna 1602 to pesticide free food in Joop C. van Lenteren Laboratory of Entomology Wageningen University The Netherlands

Transcription

1 From entomology in Bologna 1602 to pesticide free food in 2004 Joop C. van Lenteren Laboratory of Entomology Wageningen University The Netherlands

2 From entomology in Bologna to pesticide free food What are parasitoids and were they discovered by Italians? What is scientific and applied value of parasitoids? Production of pesticide free food in 2004: realistic?

3 What are parasitoids? Parasitoids: insects that are only parasitic in their immature stages, kill their host in the process of development, and have free living adults True parasites: live at the expense of their hosts without actually causing the death of the host

4 How do parasitoids develop?

5 How do parasitoids develop? DEEL ANIMATIE PARASITERING HIERNA INBRENGEN

6 Where do we find insect parasitoids? Most species in Hymenoptera (80%) and Diptera (15%) Assume there are 13.3 million species of organisms (9-40 million) 75% of all organisms are insects: 10 million species 10% of all insect species are parasitoids: 1 million species Parasitoids are very small (1 mm), many species to be discovered

7 When were parasitoids discovered? According to entomology books, until 4 years ago: in 1700 by Vallisnieri or Van Leeuwenhoek

8 When were parasitoids discovered? Europe Aristoteles ( BC) founder of entomology, mentions predatory wasps, but not parasitic wasps

9 When were parasitoids discovered? Europe Aristoteles ( BC) founder of entomology, mentions predatory wasps, but not parasitic wasps Aldrovandi ( ) - wrote the first book purely devoted to insects (1602) - depicted parasitic wasps (without knowing what they were)

10 When were parasitoids discovered? Europe Aristoteles ( BC) founded of entomology, mentions predatory wasps, but not parasitic wasps Aldrovandi ( ) - wrote the first book purely devoted to insects (1602) - depicted parasitic wasps (without knowing what they were) - and described emergence of parasitic larvae from caterpillar (without knowing what they were)

11 When were parasitoids discovered? After Aldrovandi many other scientists mentioned emergence of larvae from caterpillars: Mouffet, Redi, Malpighi, Ray, Lister, Goedaert, Swammerdam, van Leeuwenhoek, Merian etc. Initially most of them either said they did not know the origin or supposed spontaneous generation Later several of them speculated about origin of these larvae and still later (between 1670 and 1700) a few observed parasitism The whole developmental cycle of parasitoids was known in most European countries around 1750

12 Antoni van Leeuwenhoek ( ) 1687 Observed emergence of parasitoid larvae from caterpillar, suggested that eggs have been laid in caterpillar by other insect Wrote later extensively about other parasitoids that emerged from hosts (3 of his letters between ) 1700 Published complete developmental cycle including egg laying based on own observation (reads like crime story)

13 Antoni van Leeuwenhoek ( )

14 Antoni van Leeuwenhoek ( ) Aphidius sp.

15 Antoni van Leeuwenhoek ( )

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17 Jan Swammerdam ( ) Extensive discussions about origin, refuted explanations of Aldrovandi, Mouffet, Goedaert, Redi and others in quite aggressive terms

18 Jan Swammerdam ( ) Extensive discussions about origin, refuted explanations of Aldrovandi, Mouffet, Goedaert, Redi and others in quite aggressive terms Speculated correctly about the origin of parasitoids, and then on page 709 of the Book of Nature: Painter Marsilius told him: flies lay eggs in caterpillars, and from these the worms develop that you have so often seen

19 When were parasitoids discovered? 1675 Jan Swammerdam and Otto Marsilius: observation and description of complete life cylce of parasitoid on p. 709 of the Book of Nature, first European description Discovery of insect parasitoids in Europe 25 years earlier than van Leeuwenhoek and Vallisnieri did In other European countries: later What about the rest of the world: Later: Africa, America, most of Asia (incl Japan), but.

20 When were parasitoids discovered? China Parasitoids of silkworm were first mentioned in Chinese literature around 300

21 When were parasitoids discovered? Pi Ya (New Additions to the Literary Expositor) China Full developmental cycle, including egg laying, was first described by Lu Dian in years earlier than Europe 800 years earlier than in Japan

22 From entomology in Bologna to pesticide free food What are parasitoids and were they discovered by Italians? What is scientific and applied value of parasitoids? Production of pesticide free food in 2004: realistic?

23 Research on parasitoids in Wageningen today Molecular biology Sensory physiology Neurobiology Chemical ecology Behavioural ecology - learning Evolutionary ecology Population dynamics/genetics Multitrophic relationships Individual based simulation models Biological and integrated control

24 How do parasitoids find their hosts?

25 How do parasitoids find their hosts? Search for host plant * Host stimuli: pheromones

26 How do parasitoids find their hosts? Search for host * Host stimuli: pheromones

27 How do parasitoids find their hosts?

28 Host stimuli: spy on pheromones

29 Host finding by Trichogramma: spying on sex pheromone

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31 Associative learning: where is best place to be?

32 Parasitoids learn odour, taste, colour, form and pattern

33 Plant can play an active role: advertise for bodyguards Plant + non-eating caterpillar Mechanical damage Plant + eating caterpillar Mechanical damage + spit of caterpillar

34 Which species can learn and why? Most parasitoids are specialists - attack one or a few host speciesuse specific stimuli from host plant or host, innate behaviour, fixed reactions Few parasitoids are generalists - attack many host species - first use generic stimuli from host plant, than learn to use specific stimuli through association (and unlearn and forget) Generalists need to learn because of wide spectrum of hosts and host plants that varies over space and time We currently study how they learn (molecular biology and neurobiology)

35 From entomology in Bologna to pesticide free food What are parasitoids and were they discovered by Italians? What is scientific and applied value of parasitoids? Production of pesticide free food in 2004: realistic?

36 Applied aspects Sleuth-wasps: finding drugs / explosives / human illnesses (any interesting odour..) Indicators: environmental quality Indicators: non-target effects chemicals on invertebrates Biological control of pests

37 Beneficial function of parasitoids worldwide Herbivores (potential pests) are kept at low population levels on all land covered with plants: almost 70% of total surface of continents (89.5 million km2) Worldwide 95% (about 38,000 species) of potential pests is under natural control on land with agriculture (44.5 million km2); remaining 2,000 pest species need some form of control Biological control is applied on 3 million km2

38 How do we find effective parasitoids? Each pest species has > 100 species/ 1000nds of strains of natural enemies, but ony a few are effectively reducing pest Specific - no negative side effects on non-target organisms Adapted to target climate Well synchronised with development of host Higher kill rate than rate of reproduction of host Effective host searching Cheap to produce Finding a good natural enemy: 5-10 years, 2 million Euro Selection criteria based on our pure scientific research

39 Mass production, quality control, training and fine-tuning of parasitoids before field releases all based on our pure scientific research

40 Biological Control Agents: 100 years ago INSECTS

41 Biological Control Agents: today WEEDS INSECTS VIRUSES MITES VERTEBRATES NEMATODES BACTERIA FUNGI PROTOZOA

42 World wide: more than 125 natural enemy species commercially available

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44 Mass production and release of nat. ens.: biotech! Release of Encarsia worldwide: 2.5 billion / year Release of Trichogramma spp. worldwide: 1,500 billion / year

45 Mass production of natural enemies

46 Release of natural enemies

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48 Release of natural enemies

49 From entomology in Bologna to pesticide free food What are parasitoids and were they discovered by Italians? What is scientific and applied value of parasitoids? Production of pesticide free food in 2004: realistic?

50 Example: IPM programme for tomato in temperate zones: largest greenhouse vegetable world wide Pests and diseases 10 insect / mite pests 2 nematode pests 5 fungal diseases 1 bacterial disease 2 virus diseases

51 IPM Programme for tomato in temperate zones 10 insect / mite pests 15 natural enemies: predators, parasitoids and pathogens predators Phytoseiulus persimilis

52 IPM Programme for tomato in temperate zones 10 insect / mite pests 15 natural enemies: predators, parasitoids and pathogens predators parasitoids Encarsia formosa

53 Recently added natural enemies to Dutch glasshouses Tropical Alcippe brunnea birds to control caterpillars 20 per hectare

54 Recently added natural enemies to Dutch glasshouses Reptiles from Indonesia to control thrips and scales insects, 250/ha

55 IPM Programme for tomato in North Europe 10 insect / mite pests 15 natural enemies 2 nematode pests resistant cultivars, soilless culture 5 fungal diseases biocontrol (antagonists), climate management, resistant cultivars 1 bacterial disease pathogen free seed, soilless culture 2 virus diseases resistant cultivars, biol. vector control Pollination bumble bees > Overall: 99% reduction in pesticide use

56 Chemical control of diseases interferes with biocontrol of pests Biological control of diseases Gray mold (Botrytis): antagonistic yeasts ++ Mildew (Oidium): antagonistic yeasts & partial resistance ++ Soil diseases - antagonistic microorganisms +

57 Production of pesticide free food in 2004: realistic? Production of pesticide free food is possible, Not only in greenhouses But reorganization of agricultural research needed From extreme reductionist approach.....to agroecosystem approach

58 Production of pesticide free food: realistic and needed!! New form of agriculture needed with respect for environment: - independent of fossil energy, - less polluting, - fewer negative effects on biodiversity Crop protection in new agriculture: - based on inherent strength of agro-ecosystem (plant resistance, biological control, crop rotation, landscaping) - and where necessary enhanced by biologically based methods (breeding, augmentative biocontrol, semiochemicals, etc. etc.)

59 What determines production level of crop? Potential growth growth determining factors radiation temperature crop properties Attainable growth growth limiting factors water nutrients Actual growth crop protect. growth reducing factors pests diseases weeds Production level

60 PESTICIDE TREADMILL Heavy reliance on pesticides Little emphasis on ecosystem Lewis, van Lenteren, Phatak & Tumlinson PNAS, 94, , November 1997

61 PESTICIDE TREADMILL THERAPEUTICS Broad spectrum chemicals Biopesiticides & Biological Agents Shift to use of soft interventions Heavy reliance on pesticides Little emphasis on ecosystem Lewis, van Lenteren, Phatak & Tumlinson PNAS, 94, , November 1997

62 PESTICIDE TREADMILL THERAPEUTICS Broad spectrum chemicals Biopesiticides & Biological Agents Shift to use of soft interventions Heavy reliance on pesticides Little emphasis on ecosystem ECOSYSTEM Shift from reductionist approach to emphasis on understanding multitrophic interactions Use inherent strengths of ecosystem Lewis, van Lenteren, Phatak & Tumlinson PNAS, 94, , November 1997

63 PESTICIDE TREADMILL Heavy reliance on pesticides Little emphasis on ecosystem THERAPEUTICS Broad spectrum chemicals Biopesiticides & Biological Agents Shift to use of soft interventions ECOSYSTEM Shift from reductionist approach to emphasis on understanding multitrophic interactions Use inherent strengths of ecosystem Therapeutics as backup Strong knowledge and emphasis on ecosystem strengths TOTAL SYSTEMS MANAGEMENT Lewis, van Lenteren, Phatak & Tumlinson PNAS, 94, , November 1997

64 Work in Wageningen: systems approach and detail

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69 Spring: migration of beneficial insects from hedges to field, DNA profiling

70 In Holland, UK and.. Italy

71 And in tropics Natural-enemy banks: field edges / natural elements rice

72 FROM VAST MONOCULTURES TO.

73 Base pest management on knowledge of agroecosystem Pest management research in symphony with other agronomic studies, not separate International Organization of Biological Control (IOBC) helps you So become member:

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77 Developments in use of biocontrol worldwide Continents (- Antarctica): 134,000,000 km2 Covered with vegetation: 89,5 Agricultural/veterinary activity on 44,5 Forest 25 Grass 5 Arable land 13,5 Perennual crops (orchards) 1

78 CHEMICAL AND BIOLOGICAL CONTROL COMPARED Chemical control Biological control Number of ingredients tested > 1 million 1,000 Success ratio 1 : 30,000 1 : 20 Developmental costs 100 million $ 2 million $ Developmental time 10 years 10 years Benefit / cost ratio 2 : 1 20 : 1 Risks of resistance large small Specificity very small very large Harmful side-effects many nil/few