Adapted from IFOAM Training Manual on
Organic FarmingIn the Tropics
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Natural Enemies“Friends of the
Farmer”A presentation about natural pest control practices
Topics To Cover
• Ecology of Pests and Diseases(insect populations, life cycles, impacts of pesticides)
• Promoting Natural Enemies(their uses, characteristics, managing)
• Bio-Control(releasing natural enemies, using bacteria, fungus and viruses)
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Ecology of Pests and Diseases
What is Ecology???
“Study of relationships between organisms and their environment”
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Ecology of Pests and Diseases
• Insect POPULATIONS are the problem, not individual insects.
• Different ecological factors can determine whether an insect population will become a “pest” or maintain in balance with the crop.
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INSECTPopulation
Temperature
Wind
Humidity
Light
Other membersof the species
Competitors
Food sources
Natural enemies
Ecology of Pests and Diseases
Factors Influencing Insect Ecology
Source: IFOAM Training Manual
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Ecology of Pests and Diseases
• Who is the pest (identify which insect is causing the damage)
• What type of pest (burrower, leaf chewer, sap sucker, etc.)
• Where is the damage (i.e., leaves, stalk, roots)
• When is the pest attacking the crop (in the spring, summer, before/after rain, when crop ripens)
• Why is the pest attacking (to lay eggs, larvae feeding)
Important considerations!
Ecology of Pests and Diseases
Pupa
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Egg Mass
Life Cycle of rice yellow stem borer (Scirpophaga incertulas)
Larva(5 stages)
Adult Moths
Common Life Cycle
Ecology of Pests and Diseases
• When pest populations are abundant there is more food for predator insects (increase in predator population)
• When the pest populations are low there is less food for the predators (decrease in predator populations)
Therefore, pest and predator insect populations are always in equilibrium
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The Predator Prey Relationship
Ecology of Pests and Diseases
What do you think happens when you use a pesticide that kills ALL
insects, including the beneficial, predator insects???
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Pesticide Use
Ecology of Pests and Diseases
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Negative Impacts of Pesticides:• Return of pest populations due to elimination of natural enemies
- phenomenon known as Resurgence• Development of insecticide-resistant pest populations
- pesticide no longer kills the pest!
Ecology of Pests and Diseases
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Source: IFOAM Training Manual
Promoting Natural Enemies
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Uses and Characteristics of Natural Enemies
Pathogens (fungi, bacteria or viruses)
Predators (spiders, lady beetles, syrphid flies)
Parasitoids(wasps or flies)
Nematodes(tiny soil dwelling worms)
Promoting Natural Enemies
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Source: IFOAM Training Manual
Managing Natural Enemies
Bio-Control
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Releasing Natural Enemies
Source: IFOAM Training Manual
Bio-Control
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Why Use Biological Control???
• It is based on the understanding that living systems are complex and vary (pesticides are formulated, and do not accommodate for variations)
•releasing natural enemies can be done before crop pests become a problem (keeping the populations in check), or when the pest becomes a problem (has versatility)
Use of Trichogramma to control the tomato fruitborer
The tiny black wasps (Trichogramma brasiliensis) search the eggs of the tomato fruitborer to lay their own eggs into them. Instead of a fruitborer larva, atiny wasp emerges out of the egg.
Trichogramma is harmless to the tomato plant. It is mass reared and can be released into the field on “trichocards”, containing several thousand parasitoid eggs.
In India, a trichocard containing 20,000 parasitoid eggs costs only Rs.20 to 30 (≈ US$ 0,5).
Example of Bio-ControlStages of the
Tomato Fruitborer lifecycle
Eggs
Adult
Pupa
Larvae
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Photo CreditsSlide One
• www.goldenacregarden.com/.../beneficial.htm • thailand.ipm-info.org/bt/Bt_Basics.htm• savanna.lternet.edu/gallery/kbs/KBS_Ha_eating_SBA
Slide Two• riddimmaker.smugmug.com/keyword/ladybug
Slide Three• http://www.ramsar.org/pictures/wwd2004-india-keoladeo1.jpg• http://community.iexplore.com/photos/journal_photos/misty-morning-
in-binsar.jpg• www.abroadviewmagazine.com/.../def_land.html
Slide Five• IFOAM Training Manual
Slide Seven• http://www.knowledgebank.irri.org/IPM/stemborers/image31.jpg• http://www.knowledgebank.irri.org/IPM/stemborers/image29.jpg• http://www.knowledgebank.irri.org/IPM/stemborers/image33.jpg• http://www.knowledgebank.irri.org/IPM/stemborers/image32.jpg
Slide Nine• http://www.fao.org/ag/icons/19463.jpg• http://www.indiatravelogue.com/images1/wildlife/grasshopper.jpg
Slide Ten• http://whatsthatbug.com/images/aphids_closeup.jpg• thailand.ipm-info.org/images/natural_enemies/...
Slide Eleven• IFOAM Training Manual
Slide Twelve• www.hampshirecam.co.uk/ws04/spider.jpg• www.dpw.wageningen-ur.nl/.../parasitoid.jpg • 80.194.73.68/.../Portals/2/Images/Fungi.jpg • http://www.entomology.wisc.edu/mbcn/nema.jpg
Slide Thirteen• IFOAM Training Manual
Slide Fourteen• IFOAM Training Manual
Slide Fifteen• http://www.uoguelph.ca/research/news/articles/2005/June/
aphid_biocontrol.shtml• http://www.biofac.com/Fruit___Vegetables/bobbybro.JPG
Slide Sixteen• http://www.knowledgebank.irri.org/ricedoctor_mx/
Seed_and_Grain_Symptoms/image18.gif
Slide Seventeen• www.mpg.de/.../Web_Pressebild.jpeg