Chapter 21

Integrated Pest Management for Greenhouse Crops

Biological Insect Pest Control Tactics

Biological methods are the use of beneficial organisms that can be used in a greenhouse to reduce insect pest populations. Biological control of greenhouse insect and mite pests can be achieved through release of bio-control agents like predatory mites, pirate bugs, soil-dwelling mites, and parasitic insects. Biological control agents (natural enemies or beneficials) typically will not entirely eliminate the target insect or mite pest. Implementing a biological control program in a greenhouse is management intensive and requires more knowledge on the part of the grower than for traditional pest control programs.

Predators

A predator is typically an insect or insect-related animal that attacks or feeds on a host or individual pest. This attack is typically part of the predator's natural feeding cycle. The ladybird beetle is the most common greenhouse predator feeding on aphids. Lacewings feed on aphids, scales, mealybugs, thrips, mites, and insect eggs. The larvae of syrphid flies (also called “flower flies”) consume aphids and small ants.

Parasites

A parasite or parasitoid is an organism that attacks and kills a single host. Typically the parasite completes all or part of its life cycle in or on this individual pest. When the eggs hatch, the immature or larval stages of the parasite develop by feeding on and killing the pest. Parasitic insect species will usually attack only one species of pest because they are highly specialized.

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