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Recent Advances in Biological Control of Key Pests in Mauritius

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DeSIRA project
Integrated Pest Management as a Climate Change Adaptation in Agriculture

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Recent Advances in Biological Control of Key Pests in Mauritius

  1. 1. Sub-Activity 1.1.3.1.1 Integrated Pest Management as a Climate Change Adaptation in Agriculture Dr Lalini Unmole Principal Research Scientist Entomology Division 19th September 2020 Recent advances in biological control of key pests in Mauritius
  2. 2.  Mauritius vulnerable to the effects of climate change  Pest problems likely intensified in the forthcoming years due to • Pest resurgence • Incursions of new pests  Sole reliance on pesticides for pest control is not advisable Introduction (1)
  3. 3.  Represents risks of: Environmental contamination, Resistance to pesticides, Decimation of beneficial organisms Pesticide residues in agricultural produce (10 /498 samples)  FAREI has R&D programme on IPM of which biological control is key component Introduction (2)
  4. 4. Biological control  The use of living organisms to control pests:  Includes: • Predators • Parasitoids • Pathogens
  5. 5. Predator  Free living species that consume a large number of prey during its lifetime
  6. 6. Parasitoid  Lays its eggs on or in the body of an insect which is then used as a food for developing larvae. The host is ultimately killed.
  7. 7. Pathogens Nematodes Fungi Viruses Bacteria
  8. 8. Advantages of biological control  Absence of toxic residues  No development of resistance by the pest  No killing of pollinators & other beneficial insects  No environmental contamination  Long-term solution to a pest problem
  9. 9. Aim  Promotion of biological control through production and releases of bio-control agents
  10. 10. Objectives  Search for existing biocontrol agents of five key pests  Rear recovered biocontrol agents for evaluation of effectiveness  Develop protocols for mass rearing biocontrol agents  Train interested potential entrepreneur on mass rearing
  11. 11. Methodology  Island wide survey  Samples examined under microscope  Detect biocontrol agents  Rear to confirm identity
  12. 12.  Major pest on vegetable crops in greenhouses.  Extract sap from under leaves & secrete honey dew.  Honey dew nutrient source for sooty mould.  Reduces photosynthesis & severely damages host plants  20-25% yield loss 1. Biological control of whiteflies Damage Adult (1.2mm) & nymphs of whiteflies
  13. 13.  Difficult to control with insecticides  Usually farmers apply insecticides intensively  Previously Encarsia sp. identified as potential biocontrol agent 1. Biological control of whiteflies Adult Encarsia sp. (0.7 mm) Parasitised nymph (black)
  14. 14.  Releases in greenhouses led to 77%-80% parasitism in whitefly nymphs  Biological control a viable option for whitefly control in greenhouses  Identify biocontrol agents to target different stages of whiteflies for improved control 1. Biological control of whiteflies Crop No. of insecticide applications Farmers’ Practice Release of parasitoids English cucumber 16 4 Tomato 24 6
  15. 15. Biological control agents recovered Eretmocerus sp. Parasitised nymph (2nd instar)Adult (0.6 mm)
  16. 16. Micromus timidus Biological control agents recovered Larva Adult (9mm)
  17. 17. Biological control agents recovered Exochomus sp. Larva Adult (3.2 mm)
  18. 18. Biological control agents recovered Larva Adult (1.8 mm) Scymnus constrictus
  19. 19. Anthocorid bug Biological control agents recovered Immature stages Adult (3-4 mm)
  20. 20. 2. Biological control of red spider mites, Tetranychus spp.  Key pest of vegetables & ornamentals  Through their high reproductive capacity they can destroy plants rapidly  Cause damage by feeding on plant tissue & sap  Results in yellow spots on leaves  As damage increases whole leaves turn yellow & eventually the plant may die Adult(0.4 mm)
  21. 21.  The predator Phytoseiulus persimilis effective in greenhouses of rose, strawberry, English cucumber & sweet pepper 2. Biological control of red spider mites, Tetranychus spp. Phytoseiulus persimilis (0.5 mm)
  22. 22.  Releases of P. persimilis in greenhouses  Not effective on tomato crop  Identify suitable predators of red spider mites on tomato 2. Biological control of red spider mites, Tetranychus spp. Crop No. of acaricide applications Farmers’ practice After release of predators Strawberry 24 4 English cucumber 16 4 Sweet pepper 28 8
  23. 23. Biological control agents recovered Predatory mites (0.5 mm)
  24. 24. Biological control agents recovered Stethorus sp. Larva Adult (1mm)
  25. 25. Biological control agents recovered Nymph Adult (1 mm) Scolothrips sp.
  26. 26. Biological control agents recovered Franklinothrips vespiformis Nymph Adult (2.5-3.0 mm)
  27. 27. Biological control agents recovered Chrysoperla sp. Larva Adult (10-20 mm)
  28. 28. Biological control agents recovered Feltiella sp. Larva feeding on adult mites Adult (2 mm) Larva feeding on mite eggs
  29. 29. Biological control agents recovered Oligota sp. Larva Adult (1-2 mm)
  30. 30. Biological control agents recovered Wollastoniella sp. Nymph Adult (1.2-1.5 mm)
  31. 31. 3. Biological control of yellow sugarcane aphid, Sipha flava  Key pest on pasture grass - herbe d’argent an important fodder crop in deer ranches  Has a high reproductive capacity Sipha flava (2mm)
  32. 32.  Feeding causes leaves to turn red & eventually dry out  Not appropriate to apply insecticides in ranches  Introduction of Diomus terminatus by Agricultural Services 3. Biological control of yellow sugarcane aphid, Sipha flava Diomus terminatus
  33. 33. Biological control agents recovered Cheilomenes sulphurea Larva Adult (6.2 mm)
  34. 34. Biological control agents recovered Brumus suturalis Larva Adult (3.2 mm)
  35. 35. Biological control agents recovered Scymnus sp. Larva Adult (1.5-2.0 mm)
  36. 36. Micromus timidus Biological control agents recovered Adult (9 mm)Larva
  37. 37. Paragus borbonicus Biological control agents recovered Larva Adult (3-4.5 mm)
  38. 38. Biological control agents recovered Larva Allograpta nasuta Adult (6-7 mm)
  39. 39. 4. Biological control of thrips  Key pest of vegetables & ornamentals  Feed by scraping outer layer of host tissue & sucking out cell contents  Silver-white spots on leaves that turn brown or rusty-red  Significant leaf damage resulting in reduction of photosynthetic area  10-50% yield loss Thrips tabaci (1mm)
  40. 40.  Thrips difficult to control with pesticides  Intensive use of chemical insecticides has led to thrips populations developing resistance  Study biological control initiated 4. Biological control of thrips
  41. 41. Biological control agents recovered Jumping spider (4 mm)
  42. 42. Biological control agents recovered Triphobius sp. (0.7 mm)
  43. 43. Biological control agents recovered Franklinothrips vespiformis Nymph Adult (2.5-3.0 mm)
  44. 44. 5. Biological control of fruit flies Zeugodacus cucurbitae female (8mm)Bactrocera dorsalis female (8mm) Oriental fruit fly Melon fly
  45. 45. (1-20/fruit)
  46. 46. 100 fruits = 1000 emerging female fruit flies 1 female lays 1000 eggs Potentially 1000 females = 1.0 M fruit flies 20 eggs/fruit 10 females 20 adults emerging
  47. 47.  Management of fruit flies is difficult  Investigate on biological control of fruit flies 5. Biological control of fruit flies
  48. 48. Psytallia fletcheri Biological control agents recovered
  49. 49. Biological control agents recovered Fopius arisanus (4 mm) Tetrastichus giffardianus
  50. 50. Augmentorium Multiplication of parasitoids at field level
  51. 51. Funding by EU • Equipments • Capacity building • Refurbishment of building
  52. 52. Way forward  Pursue survey on natural enemies of key pests  Study effectiveness of biocontrol agents  Promote promising species among farmers  Develop protocols for mass rearing  Train interested parties in rearing of biocontrol agents
  53. 53. Outcome  Effective biological control agents of key pests identified  Protocols for mass rearing biocontrol agents developed  Biological control adopted by farmers  Reduction in pesticide use
  54. 54. Impact of the project  Food productivity & safety improved  Reduction in imports and use of insecticides  Reduction in environmental and health hazards  Revenue generation – opportunity for agri-business  Creation of employment
  55. 55. Conclusion  Rich fauna of biocontrol agents  Opportunity for commercial production of biocontrol agents  Ensure plant biodiversity  Judicious use of pesticides  Favour safer products
  56. 56. THANK YOU

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