Natural enemies2

Adapted from IFOAM Training Manual on

Organic FarmingIn the Tropics

Fertile Ground:East/West Sustainability Network

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)

Fertile Ground: East/West Sustainability Network i

Fertile Ground: East/West Sustainability Network 1

Ecology of Pests and Diseases

What is Ecology???

“Study of relationships between organisms and their environment”



• 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.


INSECTPopulation

Temperature

Wind

Humidity

Light

Other membersof the species

Competitors

Food sources

Natural enemies


Factors Influencing Insect Ecology

Source: IFOAM Training Manual



• 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!


Pupa


Egg Mass

Life Cycle of rice yellow stem borer (Scirpophaga incertulas)

Larva(5 stages)

Adult Moths

Common Life Cycle


• 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


The Predator Prey Relationship


What do you think happens when you use a pesticide that kills ALL

insects, including the beneficial, predator insects???


=

Pesticide Use



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!




Promoting Natural Enemies


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



Managing Natural Enemies

Bio-Control


Releasing Natural Enemies


Bio-Control


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



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

Natural enemies2

Documents

viruses fertile ground

environment fertile

tropics fertile ground

versatility fertile

natural enemies source

natural enemies friends

diseases insect populations

natural pest control