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close this bookBio-Intensive Approach to Small-Scale Household Food Production (IIRR, 1993, 180 p.)
close this folderPest management
close this folderAlternative pest management
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View the documentCultural method of pest control
View the documentBiological pest control
View the documentEncouraging predators
View the documentBotanical pest control

Biological pest control

Biological pest control is the suppression of pest populations by living organisms such as predators, parasites and pathogens. These agents are responsible for keeping pests under control most of the time.

Predators are usually other insects and spiders. Both, but particularly spiders, feed on a wide range of insects. Adults and immatures are often predatory.

Praying mantis, Dragonfly, Damselfly, Assassin bugs
Feed on all types of insects.

Praying mantis

Lacewings, White-banded clerid Robber files Feed on aphids and soft-bodied insects.


Ground beetles, Whirligig beetles, Rave beetles, Tiger beetles, Green carabid beetles
Feed on other insects.

Ground beetles

Ladybird beetles feed on scales and aphids only. They eat 40-50 insects per day. Their larva eat even more.

Ladybird beetles

Toads, snakes and spiders eat insects and other garden pests. Toads eat as many as 10,000 insects and other pests in three months, including cutworms, slugs, crickets, ants, caterpillars and squash bugs.

Toads, snakes and spiders


Some birds are omnivorous. Some examples from the temperate zone provide a good illustration of what birds eat. A house wren feeds 500 spiders and caterpillars to her young in one afternoon; a brown trasher consumes 6,000 insects a day; a chickadee eats 138,000 canker worm eggs in 25 days; and, a pair of flickers eats 5,000 ants as snack.


Parasitic insects are usually small flies or wasps which attack one or a few closely related pest species. They are parasitic in their larval stages but free-living as adults.

Tachinid flies, Braconid wasps

Complete their life cycle on insect pests. They usually attack the egg of the host pest or the caterpillar by laying an egg into its body. The wasp larva hatches inside the caterpillar body and feeds on it.

Tachinid flies, Braconid wasps

Trichogramma spp.

Attacks eggs of butterflies and moth. This wasp produces very few side effects on beneficial insects.

Trichogramma spp.

Epidinocarsis lopezi

Feeds and reproduces on mealybugs of cassava. It has the ability to establish itself in cassava fields.

Epidinocarsis lopezi